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One of the most useful rhetorical concepts is called “topoi.” “Topoi” are useful tools in developing sermonic content, yet the tool is little known to those who have not been taught classical rhetorical theory.
You may well find that having a list of various topoi on hand
when developing your sermon
is remarkably productive. 
It has been said that the single fastest way to increase productivity is by the addition of “tools.” “Topoi” are tools in the rhetorical chest of productivity and sermonic construction. They effectively generate ways to introduce a sermon, explain a truth or principle, illustrate a concept, conclude a message, apply the passage, or FRAME the significance of the passage & sermon.
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In this example, Alistair Begg frames the passage and his message by developing the contrast between . . .
“parted from them . . . . . and returned to Jerusalem with great joy.”
It is the parting of Jesus from his disciples after three years of personal ministry, contrasted with the emotional reaction of joy, that Begg will use to frame and develop his entire message. 
It is juxtapositioning of those two thoughts — Leaving & Joy — that are contrasted and heightened!
“. . . but wait a minute!
How is it that they would now return with such great joy?”
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The Topos Of Contrast:
The topoi can be labeled “the topos of contrast.” Perhaps the best way to explain the concept of “topoi,” and this particular “topos,” is by an example.
Here is the audio link of this clip (and a transcript) exemplifying this “topos”. . . . .
when I come, as I came this past week, to the familiar material here at the end of Luke 24—and you should have a finger in Acts chapter 1, both of these books written by Doctor Luke himself—I said to myself, you know, “What is surprising about this story? What is there, as I read the record here of what took place, that, if you like, catches me off guard or causes me to say, ‘But wait a minute, that is surprising’?” And I got my answer in Luke 24:52, where it says of the disciples that after Jesus had parted from them and returned and was carried up into heaven, that “they worshiped him and returned to Jerusalem with great joy.” “With great joy.” “Oh,” I said to myself, “but wait a minute! How is it that they would now return with such great joy?”
It was Juliet, wasn’t it—of Shakespeare’s Juliet, that is—that informed us, or informed Romeo, that “parting is such sweet sorrow”? Well, I’m not so sure about the “sweet” part. Because saying goodbye to someone that you love so easily turns the colors of the morning into a dull gray. When you stand on the railway platform, fingers intertwined with your lover, you dread the arrival of the train that is going to take you away. Simultaneously, you look forward to the train, wishing that it would come even faster, because in this strange manner it would quickly relieve the agony of parting.
What lover ever sang when parted from her beloved? Where and what heart was ever blithe in the moment of farewell? Depending on your vintage, you will have grown up with whoever was the focus of your affections singing songs that made this perfectly clear. So, for example, you know:
The dawn is breaking, it’s early morn;
The taxi’s waiting, [it]’s blowing [its] horn;
[And] already I’m so lonesome I could die.
So kiss me and smile for me,
[And] tell me that you’ll wait for me,
[And] hold me like you’ll never let me go.
Of course, that’s Johnny Denver. The hit was with Peter, Paul, and Mary. Interviewed by the BBC, this is Denver: “That song was very personal and special to me. It doesn’t conjure up 747s as much as the simple scenes of leaving. Bags packed and standing by the front door, taxi pulling up in the early morning hour, the sound of a door closing behind you, and the thought of leaving someone you care for very much. It still strikes a lonely and anguished chord in me, because the separation still continues.” And what an irony, that he died piloting that little plane.
What of the last farewell, when separated by death? You say, “Oh dear me, what brought on this dreadful sentimentalism in you, Pastor? What is happening to you?” No, this is not just sentimentalism. Because where hearts are bound together—where hearts are bound together—when souls have been entwined, then the breaking of those links inevitably brings pain and sadness.
Now, with that in mind, go back and look at what it says in verse 52: “And they … returned to Jerusalem with great joy.” How different from the reaction of Mary in the garden, remember? Jesus had to say to her, “[Mary,] do not cling to me, for I have not yet ascended to the Father; but go to my brothers.” “Go and tell them.” Because remember, Jesus had been preparing his disciples for this very day. You read of this in the middle of John’s Gospel, around chapter 16. Jesus says to them, he says, “Because I have said these things to you, sorrow has filled your heart. … [But] it is to your advantage that I go away.”
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Begg’s very last comments reveal how that contrast significantly framed the entire message.
“Those who longed for his companionship learned to rejoice in his absence.”
P.S. Another interesting, simple, and quick example of “contrasts” from Alistair Beggs message @28:52
“It is wrong that it should paralyze us. It is right that it should humble us!”
1. Here is a partial list of potential topoi that can help generate ways to develop a message, frame your sermon, formulate the BigIdea, build an introduction or conclusion, expand the applications . . . . .
Topoi: Becoming An Idea Generator
Topoi: The Topoi of “Place”
Topoi: In It Alone
Topoi: A Critical Concept Part #1
Topoi: A Critical Concept Part #2
Topoi: Topoi of Process
Topoi: Topoi of Responsibility
Topoi: Vertical & Horizontal
Topoi: Another Topoi: The Missing Link
Topoi: Another Topoi: Contributed or Caused
Topoi: Another Topoi
Topoi: Another Topoi: Definition
Topoi: Here But Not There
Topoi: The Extremes
Topoi: Another Useful Topoi
Topoi: Critical To Options
Topoi: The Motive
Topoi: Intentional or Accidental
Topoi: What It Is Not
2. This is one way to handle the passage. There are many other approaches to developing the passage and that is what makes preachers different in their approach & effectiveness.