Josh Moody describes the affections as:

Affections are the movement of our thoughts, feelings and will towards a desired object, person or event. An affection is what inclines us to something (whereas an effect is what results from something).  Affections are what move us towards action. … When our feelings and our thoughts are combined with a decisive will-to-action, then the internal event that generates this movement is called ‘affections.’

Many preachers fall into pure intellectualism or pure sensationalism.  Intellectualism is all content with no power, persuasion, or passion. The idea is that the Spirit will do whatever work is necessary without any movement on our part.  Sensationalism runs on sheer emotion, appealing to the touchy-feeling notions with little appeal or connection to the sacred text of Scripture.  Both swing the pendulum too far in their respective directions.

Preachers must preach with both the mind and the emotions together, working as one.  Paul told the Corinthian church:

11 Therefore, knowing the fear of the Lord, we persuade others. But what we are is known to God, and I hope it is known also to your conscience.12 We are not commending ourselves to you again but giving you cause to boast about us, so that you may be able to answer those who boast about outward appearance and not about what is in the heart.

We fear the Lord because, one day, we shall have to give an account to him (2 Corinthians 5:10).  Later, Paul says that “the love of Christ controls us, because we have concluded this: that one has died for all, therefore all have died; and he died for all, that those who live might no longer live for themselves but for him who for their sake died and was raised” (2 Corinthians 5:14-15).

The persuasion and compulsion that takes place in the heart of the preacher is out of fear and love of our Lord–so that fear and love would rest in bringing reconciliation between the sinner and the Savior (2 Corinthians 5:18-21).  The affection of fear moves us based on the truth of the judgment seat of Christ looming.  The love of Christ compels us because of the death, burial, and resurrection of Christ, compelling all who hear to live for Him and not themselves.

Where the Notion of the Affections Are Best Found

The Psalm stand as the largest ‘book’ in the Book: 150 psalms mostly written by Solomon, but also by others by the guidance of the Holy Spirit.  Each of these Psalms hang their hat on certain nails found in the Old Testament; not the least of which are God as Creator (Genesis 1-2), God as Deliverer (with the Exodus in Exodus 14-15), and God as Judge and Reconciler (with the Exile and Return).  We see from the Psalms how our heart the writer’s soul pants for God “as a deer pants for flowing streams… My soul thirst for God, for the living God” (Psalm 42:1-2).  He recalled how he would go to the Temple, shouting and singing, and “keeping festival” (v. 4).  Twice, he calls God “his salvation” (v. 5, 11). As He rescued Israel from Egypt, so God will continue to rescue His people from their enemies.

Psalm 47 begins, “Clap your hands, all peoples!  Shout to God with loud songs of joy” [why?] “He subdued peoples under us, and the nations under out feet. He chose our heritage for us, the pride of Jacob whom he loves” (Ps 47:1-4).  The affections and effusion of emotions is not happening in a vacuum, but is fueled on truth that the people of God are His chosen people from the time of Jacob on!

The point is, all through Scripture, you could never see emotion and affections for their own sake, but only to compel and persuade others to Christ.