Thy love did read by rote, that could not spell.

But come, young waverer, come, go with me,

In one respect I’ll thy assistant be,

For this alliance may so happy prove

To turn your households’ rancor to pure love

On the morning after Romeo and Juliet meet, Romeo visits Friar Lawrence's cell bright and early, asking if the holy man will consent to marry the young couple.  Lawrence is surprised to see that Romeo has gotten over his "love" of Rosaline so quickly and moved on to someone else.  He says, "O, she knew well / Thy love did read by rote, that could not spell" (2.3.94-95).  In other words, he credits Rosaline for her refusal of Romeo because, clearly, Romeo did not truly love her.  However, immediately following this, Lawrence says to Romeo,

But come, young waverer, come, go with me.In one respect I'll thy assistant be,For this alliance may so happy proveTo turn your households' rancor to pure love.  (2.3.96-99)

Believing Romeo to be "wavering" in his love, first in his love for Rosaline and now for Juliet, Lawrence still agrees to marry him and Juliet.  He seems to hope that a marriage between the two young people will bring their families together and prevent any further violence.  This is a nice idea.  However, he is agreeing to marry two people, one of whom at least is incredibly young (Juliet is just thirteen), without their parents' permission, knowing that their families loathe one another, and with full knowledge that the groom is not the most steadfast in his love.  Had the friar never consented to marry the couple, then it seems likely that they would both remain living.

The quotes that Friar Lawrence states when introducing and implementing his plan are, by far, the most damning.

When Friar Lawrence introduces the potential plan in Act 4, Scene 1, it is clear that he is responsible for dreaming up the idea:

If, rather than to marry County Paris,                                                              Thou hast the strength of will to slay thyself,                                                         Then is it likely thou wilt undertake                                                                    A thing like death to chide away this shame,                                                 That copest with death himself to ’scape from it.                                                And if thou darest, I’ll give thee remedy. (lines 73-78)

In the above, it is clear that Juliet is only coming to seek solace and a solution.  That the friar suggests such a dangerous plan is entirely his doing, as is shown in the quote above.  It is he who suggests a plan that will render Juliet in a stage "like death."

Likewise, when the plan starts to go awry after Friar John cannot tell Romeo about Juliet's true condition, Friar Lawrence likewise admits guilt, stating that Juliet will be upset to hear that the plan has gone poorly:

"She will beshrew me much that Romeo / Hath had no notice of these accidents."  (Act 2, Scene 5, lines 26-27).  

Here, the friar realizes that he is to blame for any mishaps, and acknowledges that Juliet will be angry over the outcome.  Later in the same act, he states that Juliet is shut up in a tomb alone because of his mistakes (line 30).

Thus, in the creation of, and implementation of, the plan, Friar Lawrence admits to mistakes that ultimately bring about Romeo and Juliet's demise.

The clearest piece of evidence to indicate that Friar Laurence is guilty in Shakespeare's Romeo and Juliet is the Friar's own confession in Act 5, scene 3. In his monologue, he confesses that he married the two secretly. He further confesses to giving Juliet the sleeping potion, and says that if he did not, she would have killed herself right there. He confesses to giving a letter to Friar John explaining the plan to Romeo, and that Friar John returned the letter to him undelivered, so that Romeo never knew the contents of the message.

Had he not confessed, the deaths of Romeo and Juliet may have remained a mystery, as Friar Laurence fled from the catacombs before the arrival of the watchmen. Balthasar is found in the churchyard, and might have been implicated if it weren't for the Friar's subsequent confession.

The nurse would have known that the Friar married Romeo and Juliet, but she doesn't know of the plot that the Friar concocts to give Juliet the sleeping potion and alert Romeo, who is banished, so they can sneak away together. Juliet stops confiding in the nurse when the nurse suggests Juliet would be better off marrying Paris.

Without the Friar's confession, there wouldn't be any evidence to prove his guilt. The only witnesses are dead. The letter he penned to Romeo was returned to him by Friar John. If he hadn't had an attack of conscience, he would certainly have gone to his grave without anyone knowing the depth of his involvement.  

First of all, I wouldn't say that Friar Lawrence is directly to blame for the deaths of Romeo and Juliet. However, one can certainly say that he contributes in some way towards their tragic demise. Without him, Juliet wouldn't have taken the sleeping draught that led to Romeo thinking she was dead, which in turn led to his own death. Although Friar Lawrence couldn't reasonably have foreseen such a tragic outcome, he knew that he was playing with fire. For as he states in his opening monologue, each herb, plant, or flower that he picks has both poisonous and medicinal properties:

Within the infant rind of this weak flowerPoison hath residence and medicine power. (act 2, scene 3).

In giving Juliet such a powerful sleeping potion, Friar Lawrence must be aware of the dangers involved. That he's prepared to take such a risk regardless shows a certain recklessness and irresponsibility on his part.

Another choice showing Friar Lawrence's irresponsibility is his decision to marry the star-cross'd lovers in the first place. After he pronounces them man and wife he says something rather odd:

These violent delights have violent ends. (act 2, scene 6).

In other words, he understands that such strong passions as Romeo and Juliet have for each other can all too easily end in violence. To this end he urges the happy couple to moderate their love for each other. But surely this is completely unrealistic. The Friar must know the true nature of Romeo and Juliet's love, that it is passionate and all-consuming. And yet, despite this, and despite knowing what such passionate love can lead to, he goes ahead and marries them anyway, heedless of the consequences of such an irresponsible act.

Friar Lawrence plays a significant role in Romeo and Juliet's fate and is responsible not only for secretly marrying the two lovers but also for concocting the flawed plan that leads to a drastic misunderstanding on Romeo's part when he arrives at Juliet’s tomb. In act 2, scene 3, Romeo visits Friar Lawrence and explains to him that he is now in love with Juliet. Friar Lawrence is initially astonished, but he agrees to secretly marry the two lovers, saying,

But come, young waverer, come, go with me, In one respect I’ll thy assistant be, For this alliance may so happy proveTo turn your households' rancor to pure love. (2.3.89–91)

In act 4, scene 1, Juliet arrives at Friar Lawrence's cell and explains to him her desperate situation. Friar Lawrence proceeds to create a plan, which involves Juliet drinking a sleeping potion that will make it seem like she is dead. Friar Lawrence gives Juliet the vial and tells her,

Let not the Nurse lie with thee in thy chamber. [shows her a vial] Take thou this vial, being then in bed, And this distillèd liquor drink thou off,When presently through all thy veins shall runA cold and drowsy humor, for no pulseShall keep his native progress, but surcease.No warmth, no breath shall testify thou livest.The roses in thy lips and cheeks shall fadeTo paly ashes, thy eyes' windows fallLike death when he shuts up the day of life. (4.1.94–104)

Friar Lawrence then proceeds to explain that he will send a letter to Romeo in Mantua describing the plan, and Romeo will rescue Juliet from her tomb. In act 5, scene 2, Friar John explains to Friar Lawrence that he was unable to deliver the letter to Romeo, which prompts Friar Lawrence to say,

Unhappy fortune! By my brotherhood,The letter was not nice but full of charge, dear import, and the neglecting itMay do much danger. Friar John, go hence. Get me an iron crow and bring it straight Unto my cell. (5.2.17–23)

Tragically, Romeo discovers Juliet, believes that she is dead, and commits suicide beside her tomb. When Juliet awakens from her sleep, she discovers that Romeo is dead and also commits suicide. When the royal families arrive at the scene, Friar Lawrence takes responsibility for Romeo and Juliet's deaths by saying,

I am the greatest, able to do least,Yet most suspected, as the time and placeDoth make against me, of this direful murder.And here I stand, both to impeach and purge,Myself condemnèd and myself excused. (5.3.238–243)

Friar Lawrence then proceeds to explain how he secretly married Romeo and Juliet and describes how his plans to reunite the two lovers went awry.

I believe that Act 2, Scene 3, is a good place to start for finding quotes that would help support the idea that the friar is to blame for the deaths of Romeo and Juliet. This scene has the friar agreeing to help Romeo and Juliet be together.

But come, young waverer, come, go with me.In one respect I'll thy assistant be,For this alliance may so happy proveTo turn your households' rancor to pure love.

The friar isn't completely convinced that Romeo is in true love with Juliet; however, the friar sees the relationship as a possible tool that can be used to help mend the Capulet and Montague feud. It's possible that if the friar had discouraged the entire thing, Romeo and Juliet would not have wound up dead.

I think the quote that has the strongest evidence against the friar can be found in Act 4, Scene 1. Juliet has gone to the friar to weep and be consoled. She speaks of killing herself, and the friar rightly tries to talk her out of doing that; however, his suggestion is for Juliet to just appear dead:

If, rather than to marry County Paris,

Thou hast the strength of will to slay thyself,

Then is it likely thou wilt undertake

A thing like death to chide away this shame,

That copest with death himself to ’scape from it.

An if thou darest, I’ll give thee remedy.

No one is really malicious about causing Romeo and Juliet’s deaths. Their deaths are caused by a combination of circumstances and bad choices. You could argue both deaths were caused by Friar Laurence and the nurse keeping quiet about the secret wedding between Romeo and Juliet. They enabled Juliet and put her in a position she could not escape.

Juliet uses the nurse as a go-between between her and Romeo. The nurse agrees to do this because she cares about Juliet. She knows Juliet would be better off not getting involved in with a Montague, but plays along to make Juliet happy:

Then hie you hence to Friar Laurence' cell;There stays a husband to make you a wife:Now comes the wanton blood up in your cheeks,They'll be in scarlet straight at any news.Hie you to church (Act II, Scene 5).

Other than the nurse, Friar Laurence is the only other person who knows about Romeo and Juliet’s plans. He is concerned too, especially since Romeo was so recently head-over-heels for Rosaline. He marries them in secret. Once Romeo is banished, Friar Laurence gives Juliet a potion to fake her death so she will not have to marry Paris.

If, rather than to marry County Paris,Thou hast the strength of will to slay thyself,Then is it likely thou wilt undertakeA thing like death to chide away this shame,That copest with death himself to scape from it:And, if thou darest, I'll give thee remedy (Act IV, Scene 1).

I think you can definitely argue events would have turned out differently if Friar Laurence had not helped Juliet with the potion. She might have been unhappy, but she would not have died. Romeo and Juliet’s deaths are directly caused by that potion because Juliet wakes in her tomb to find Romeo has killed himself, thinking she really was dead. This prompts her to kill herself.

Shakespeare announces in the Prologue that Romeo and Juliet are ill-fated because of the unfavorable position of the stars and that they will ultimately commit suicide: "A pair of star-crossed lovers take their life." In Act I, Scene 4, even before he meets Juliet, Romeo suggests that fate is about to intercede in his life. After Mercutio's Queen Mab speech, Romeo says, in an aside,

I fear too early, for my mind misgivesSome consequence yet hanging in the starsShall bitterly begin his fearful dateWith this night’s revels, and expire the termOf a despisèd life closed in my breastBy some vile forfeit of untimely death.

Even though Friar Laurence warns Romeo not to move so quickly with his love for Juliet, he marries them anyway. This isn’t the only time that the Friar makes a hasty decision. In fact, the Friar makes several decisions throughout the course of the play that can be connected to the deaths of Romeo and Juliet - for example, he supports Romeo in his banishment, he sends a letter to Romeo that Romeo never receives, he covers up the “death” of Juliet, he leaves Juliet alone in the tomb, just to name a few.

However, the one quote that really connects the Friar to their deaths is in Act IV, Scene I.

“Take thou this vial, being then in bed,

And this distilled liquor drink thou off,

When presently through all thy veins shall run

A cold and drowsy humor, for no pulse

Shall keep his native progress, but surcease.

No warmth, no breath shall testify thou livest.

The roses in thy lips and cheeks shall fade

To paly ashes, thy eyes’ windows fall

Like death when he shuts up the day of life.”

Juliet has just learned that Tybalt has died, Romeo is banished, and that she must marry Paris on Thursday. Desperate for a solution or she’ll commit suicide, she pleads for the Friar to help her. The Friar then realizes what a mess this hasty marriage between Romeo and Juliet has caused. In an attempt to cover his tracks, he comes up with an elaborate plan: Juliet will drink a potion that makes her appear dead so that she is buried in her family’s tomb, and when she wakes up the Friar and Romeo will be waiting for her so that they can run away together in Mantua. Supposedly, Romeo will hear of all of this through a letter.

I chose the quote in which Friar hands Juliet the vial of potion as the quote that is to blame for the deaths of Romeo and Juliet because it is that vial that causes confusion and suicide. Upon making it to the tomb (without receiving the Friar’s letter), Romeo believes that Juliet is in fact dead. This is reason enough for him to commit suicide and drink the last of the potion. When Juliet wakes up from the potion, she sees Romeo and uses a sword to kill herself. Without that vial of potion from the Friar, the deaths of Romeo and Juliet could have been avoided.

In Shakespeare’s Romeo and Juliet, Romeo is clearly responsible for his own death and just as clearly at least partly responsible for Juliet’s death. Let’s look at this assertion in more detail.

First, Romeo has no business getting involved with Juliet in the first place. Their families have long been feuding, and if Romeo had taken a moment to pause and think, perhaps both Romeo and Juliet would have survived. Your first quotations can come, then, from the scenes in which Romeo woos Juliet. Pay close attention to act 2, scene 2 for the famous garden scene.

These two impulsive young people decide that they must marry at once, and indeed they do. This sets them on an even faster downhill course to tragedy, for they cannot tell their parents about their marriage, and Capulet has another husband in mind for his daughter.

Then Romeo kills Tybalt, Juliet’s kinsman. He ends up exiled. With the help of Friar Laurence, Juliet works out a plan to fake her death and then meet Romeo in another city. Romeo, however, doesn’t get the message and thinks that Juliet is really dead. In utmost despair, he goes to the apothecary and buys a strong poison specially designed to “disperse itself through all the veins” so quickly that he will fall dead at once. Romeo has determined to kill himself.

Romeo enters Juliet’s tomb, takes the poison, and calls out, “O true apothecary! Thy drugs are quick. Thus with a kiss I die.”

Juliet, however, is not really dead, and shortly afterward, she wakes up and catches sight of the dead Romeo, who has acted so quickly that he never had time to learn the truth. Juliet despairs. She kisses Romeo, trying to get enough poison to kill her, too. Then she grabs his “happy dagger,” tells it to rust within her body, and stabs herself. She dies like her beloved, falling across his body, too racked with grief to go on, and all because of Romeo’s impulsiveness.