In The Canterbury Tales, what are the morals and themes of "The Friar's Tale"?

In the Friar's Tale, Chaucer exposes the hypocrisy of the clergy as he has the Friar interact with the Summoner. For, the Friar relates a tale about a summoner, then later the Summoner tells a tale about a friar.

The Friar's story is in the form of a fabliau, which is a short, cynical narrative composed in verse. In this tale, the summoner is ridiculed because he is tricked so easily by the devil after he has boasted of his exploits.

The theme of the tale is that the summoner, who has no limitations on what he will do to people, is worse than the devil since the devil can only take the summoner when the curse put upon him is genuine, as it is from the old woman.

Critics also regard this tale as an exemplum, a well-told story of egregious behavior with a moral ending (according to eNotes' study guide) as the summoner is punished by being taken by the devil. Thus, the moral of the story is that in being so consumed with trying to trick others, the summoner leaves himself open to be tricked by the devil. That is, his deceptions have caused his own downfall.

The summoner boasts of how he earns his livelihood by extortion and "sheer deceit." He works for an archdeacon: 

No rascal craftier in this British land,
For he'd created a skillful net of spies,
Who watch for him as they roamed (procurement eyes)....
...had plenty of pimps and panders ready
At hand; like hawks that swoop from out of view
They hunted secrets and told him all they knew....

The Friar goes as far as to say that Summoners are worse than the devil because the Devil has limits with his job (he knew the man did not mean the curse against his horse and wagon), while the Summoner had no limits, and he is destroyed by the Devil as a result (the woman's curse was genuine).

In The Canterbury Tales, what are the morals and themes of "The Friar's Tale"?

The Friar's tale is about a summoner, or a person who exposes sinners, who indulges his greed by extorting money from those he catches, letting them go if they will pay him what he asks. 

The theme of the tale is the close interconnection between greed and the devil.  The moral is that those who engage in extortion and greed will soon find themselves in hell.

In Chaucer's The Canterbury Tales, what is the theme and moral lesson of The Parson's Tale?

Of the pilgrims' tales in The Canterbury Tales, the Parson's Tale stands out not only because it is the only tale in prose but also it signals a major shift from tales to entertain to religious instruction:

I wol you telle a myrie tale in prose/To knytte up al this feeste and make an ende. (Parson's Prologue, 10, ll. 46-7)

Even though the Parson promises to tell a merry tale to sum up and complete the cycle of tales told by the other pilgrim's, what he presents is a very serious and lengthy treatise on the way to heaven:

To shewe yow the wey, in this viage,/Of thilke parfit glorious pilgrymage/That highte Jerusalem celestial. (Parson's Prologue, 10, ll.49-51)

In other words, what follows will be a spiritual road map for the "perfect and glorious pilgrimage to the heavenly Jerusalem."  Specifically, the Parson's "tale" in extended sermon on the key to salvation--repentance--and an exploration of the Seven Deadly Sins: pride, envy,anger, sloth, avarice, gluttony and lechery.

The Parson's chief purpose is to remind the pilgrim's that, just as they are on a pilgrimage to Canterbury, life is a pilgrimage to heaven or hell, and the Parson's "myrie" (merry) tale will show the pilgrims how to combat the deadly sins and reach their true home, "Jerusalem celestial."

The way to heaven, acccording to the Parson, is through penitence:

. . . this wey is cleped Penitence, of which man sholde gladly herknan and enquere with al his herte,/to wyten what is Penitence. . . .(Parson's Tale, 10, ll.81-83)

In other words, man should study penitence in all its forms in order to understand its nature.  Penitence becomes important to salvation because it provides the method by which sinners can obtain forgiveness of their sins and reach heaven.

Much of the rest of the Parson's tale is a lengthy analysis of each of the Seven Deadly Sins, with a discussion of the opposite of each sin: pride/humility; envy/love of one's neighbors; anger/meekness, mild behavior;sloth/industry, work;avarice/charity;gluttony/abstinence;lechery/chastity.

The theme of the Parson's tale, then, is that man is inherently sinful and cannot reach heaven without a fundamental understanding of his sins and then consciously repent.  In order to gain that knowledge, man has to study the nature of the Seven Deadly Sins so his repentance can be genuine (because it is based on knowledge and understanding).  The tale's moral is that man cannot reach the heavenly Jerusalem without repentance.

Many critics have commented on the "rightness" of ending the Canterbury tales with a serious discussion of the most important pilgrimage of all--man's journey to heaven.

What is the symbolic meaning of "The Friar's Tale" in The Canterbury Tales?

The symbolic meaning of "The Friar's Tale" is clearly a strong attack against the Summoner, as the Friar's story includes a stereotypical summoner as its main character. Note however how this story presents summoners in a less than flattering light. As the demon-figure whom the Summoner in the story meets identifies, they are figures who are so obsessed with making money in any way whatsoever that they are just as bad as the demons that come up from the underworld to prey on poor unsuspecting individuals. Note what the fiend says to the Summoner and how he identifies a common link between them:

It seems that you're on the same errand too,

Lining your pocket, never minding how;

The same as me...

The ending of the story, where the Summoner is the "prey" that this "fiend" comes to claim because of his rapacious ways, is one that clearly shows the moral of this tale: unrestrained greed will end up in tragedy, as it takes you away from God and straight into the hands of the devil. The way in which the Summoner responds so strongly to this tale after it is over indicates that he is well aware of what an insult he has been delivered through this story.