As I prepare to preach from Exodus 2 this Sunday, I am keeping in mind these words:
So there is just one goal for a sermon–lift up Christ and his salvation. Christ likened himself to the serpent in the wilderness and spoke about his being “lifted up” (John 3:14-15). This vivid metaphor includes at least two elements. When Christ was lifted up he was: 1) crucified and 2) visible. The purpose of a sermon is to reveal the saving work of Christ vividly and powerfully to the spiritual “sight” of the hearers. Nothing could have a greater effect, for Jesus said, “When I am lifted up, I will draw all men to myself” (John 12:32). The preacher aims to be a vehicle for that drawing.
This statement is taken from Tim Keller’s lecture notes for his and Edmund Clowney’s doctorate of ministry course at Reformed Theological Seminary (2002). The audio of the entire course is available on iTunes U, and the 187-page notebook can be found here.