Friar Lawrence in Romeo and Juliet, by William Shakespeare, preaches moderation and reason. He stresses this particularly with Romeo. In Act Two, scene three, as Friar Lawrence learns not only of Romeo's dismissal of Rosaline from his heart, but also his newly found love of Juliet—a Capulet, his family's enemy—and the new couple's wish to marry immediately, he cautions Romeo. Friar Lawrence gives wise counsel, telling Romeo to move a little slower so that he does not "slip up."
Wisely, and slow. They stumble that run fast. (97)
This is, as said, excellent advice, but when Friar Lawrence comes up with his plan to have Juliet meet Romeo and Mantua—speeding things up by concocting a plan to fake Juliet's death to avoid her marriage to Paris—ironically, he does exactly what he had told Romeo not to do. The plan allows for Friar Lawrence to keep in touch with Romeo about what is happening, but there is no backup plan. No one in Juliet's house knows of the plan. Even though the Nurse does not support Romeo as before, certainly she would not have given away their plans to reunite if she has not exposed them as married. No one knows but the Friar and Romeo and Juliet. There is no contingency plan established in case Friar John cannot make it to Romeo with his message of Juliet's "death." And Romeo is given bad information because his servant does not know of the plan.
Then she is well, and nothing can be ill.
Her body sleeps in Capels’ monument,
And her immortal part with angels lives.
I saw her laid low in her kindred's vault
And presently took post to tell it you. (V.i.17-21)
Another way that Friar Lawrence does not heed his own advice is in not planning well in advance to be at Juliet's tomb when she awakes. The method of using a drug is not an exact science: a man of herbs, remedies and potions would have known this. He tells Friar John that Juliet will wake in three hours, but once the plan had broken down, he should have gone well before the appointed time. Had he planned ahead, he would have been at the tomb long before Juliet was expected to awake—as a priest, he would have raised no eyebrows in being there to pray for Juliet's soul. He would then have been there to explain what had happened to Romeo, when he arrives, prepared to die next to his wife's body.
Finally, Friar Lawrence does not practice reason when Juliet awakes and find Romeo dead. He tells her to come with him, but when Juliet refuses, he runs away. His concern should have been for Juliet before anything else—even himself—if not simply as a friend, then as her priest. Earlier Juliet threatened to kill herself rather than marry Paris. How could Friar Lawrence imagine that she would do less, left with Romeo's dead body. He flees, and Juliet kills herself.
I hear some noise. Lady, come from that nest
Of death, contagion, and unnatural sleep.
A greater power than we can contradict
Hath thwarted our intents. Come, come away.
Thy husband in thy bosom there lies dead;
And Paris too. Come, I'll dispose of thee
Among a sisterhood of holy nuns.
Stay not to question, for the watch is coming.
Come, go, good Juliet. I dare no longer stay.
Go, get thee hence, for I will not away. (V.iii.156-165)
Friar Lawrence exercises too much haste in the making of his plans and too little consideration when those plans begin to fall apart. Much like Hamlet's Polonius, Friar Lawrence shares good advice, but fails to follow it himself.