Suspiciously Specific Sermon

The power of religion is generally appreciated by those who are willing to go to religious services. As well it should be, as many religious texts were written or spoken to be appropriate to the people of the time, and often the same problems faced by them are faced by people today. Considering the number of people attending a service, it's more likely than not that one of them will find something useful in the sermon, the part specifically written and spoken to be applicable to current times.

Here, that gets a bit exaggerated. Not only is the sermon based on something current, it seems to be speaking directly to the important characters attending the service, telling them what to do to continue, start, or end the plot of the episode. As such, religious service directly invokes the power of religion to be true to life, by having the service be directly in line with the plot of the work, and by telling the characters "this is true to your life".

Depending on how much the religious leader (pastor/rabbi/imam/other) knows about the plot, or whether higher powers are personally involved, what seems like a Contrived Coincidence to the characters could be engineered circumstances.

Compare Coincidental Broadcast, where a TV broadcast just happens to be related to the plot. Could be a literal form of Deus Ex Machina.

Comic Books
"Tulip: What was the sermon going to be about? Jesse: Forgiveness."
 * In All Fall Down, Father Hector delivers a sermon on remaining strong in the face of adversity, intercut with a Flash Back to the Pantheon duking it out with the Order of Despots on the moon.
 * Parodied in Preacher (Comic Book); after a night of telling off everyone in the shithole of a town he preached in, Reverend Jesse Custer had to face them the next morning at Mass. Cut to the present day, when he's telling the story:

Film
"Elijah fled to the Mount of God, and behold, the Lord passed by and the great and strong wind rent the mountains and breaked in pieces the rocks before the Lord."
 * In Dogma, the revamp of Catholicism centers on renewed forgiveness at one church, which is exactly what two fallen angels need to get back into heaven.
 * It was the failure of this to work before the story begins that caused Bethany to realize she was straying from religion.
 * Not part of the sermon, but the mass we see Bethany attend early on includes a mention of the church's support of John Doe Jersey, which becomes important later on.
 * Two of these in Footloose, one early on establishing the town elders' opposition to rock 'n' roll, and the change of heart one near the end of the film.
 * The Witches of Eastwick. As Daryl van Horn is being blown toward the church by a gale-force wind, the sermon being spoken inside is as follows:


 * In Faster, Driver is listening to a radio pastor preach about forgiveness and letting go of vengeance as he drives around murdering the people who have wronged him. Then he goes up to the last guy on his list, and lo and behold,
 * The Englishman Who Went Up A Hill But Came Down A Mountain features a sermon that encourages the towns folk to continue building the mound that transforms the hill into a mountain on a Sunday. (This is very deliberate, though he is encouraged to do it by what page of his bible opens at.
 * In Boondock Saints, a monsignor delivers a sermon referencing the Kitty Genovese case, saying "now, we must all fear evil men. But there is another kind of evil which we must fear most, and that is the indifference of good men." The brothers McManus, after leaving the church, feel called to action and spend the rest of the movie killing off various heavyweights of Boston's organized crime world.
 * Although the scene is shown at the start of the movie, it's implied that sequentially it takes place later (perhaps even after) the main sequence of events, in which case the speech wasn't coincidental but a result of the Vigilante Man activities of the protagonists.
 * In the first Thief Of Bagdad, the thief in his early antics overhears an iman preaching about the need to earn happines. He breaks in to loudly deny it. But later, having realized he is unworthy of the princess he loves, he comes back to the mosque, and the iman repeats the message to send him off on his quest to become worthy.

Literature

 * In The Help, a sermon saying that bravery is often just having the courage to do what's right inspires Aibileen to help Skeeter with her book.
 * In every Christian romance novel where one lead (or both!) is not a church goer, they will be talked into going just where the sermon is what they need to turn to God and realize that they're in love with the other party.

Live Action TV

 * The West Wing - Toby's at temple on Friday evening, listening to his Rabbi say "Vengeance is not Jewish". He gets a phone call from Sam, who asks "By any chance, is your Rabbi giving a sermon on the death penalty?" Toby listens to another sonorous phrase demonizing the death penalty. "... yes?" This is not an accident.
 * In the Star Trek: Deep Space Nine episode "Far beyond the stars", a dream character played by the actor who plays Sisko's father gives some very specific advice to Sisko while giving a street sermon.

Theater

 * Another deliberate example: in Doubt, the priest who is suspected of molesting a little boy gives a pointed sermon on the dangers of gossip.

Web Comics

 * Fans: Rikk and his two wives come to church to discover their favorite pastor has been booted out while they were elsewhere; the new preacher's sermon is on the evils of bigamy and the trio realize their identities have been leaked.

Western Animation

 * Because of the setup of the show, this is to be expected about the show Moral Orel. It also helps that the preacher is one of the few characters who's head isn't up his ass, and thus he can make the connection transparent (though the others still won't see it). However, this isn't intentional in every episode. Orel's belief that it is is what establishes the plot in some episodes.
 * The Simpsons will occasionally have episodes where Reverend Lovejoy or Ned Flanders ties in faith to the plot.
 * Also parodied on at least one occasion. For example, during an episode where Homer and Ned have a bit of role reversal, Ned is pulled over for erratic driving after fleeing from Homer. While doing quite well on the sobriety test, a bus full of church-goers pass by, distracting Ned enough to cause him to fall over and fail the test. The next Sunday, Reverend Lovejoy announces his sermon, entitled "What Ned did."
 * Another episode played with this by having Lovejoy preach about the evils of gambling (which the episode revolved around), then after the service as everyone was leaving, you could see ads for the church's bingo night.

And so, my children, go forth, and learn the way of the Tropes, that your works shall be great in the eyes of Man...