John Donne came to be considered a "metaphysical" poet, one of whose literary skills was the use of "conceits," far-fetched comparisons of very dissimilar things. Donnes sermons reveal that he knew Augustine very well, and perhaps he noticed how Augustine did not refrain from using conceits in his own sermons. Here is one of them, used at least twice by him.In his second Enarratio on Psalm 33, Augustine summarized the lengthy interpretation of the Psalms title that he had given in his first sermon. The title referred to an incident recorded in 1 Sam 21: 12-14 when David feigns insanity in order to be thrown out of court. The key verse read in the old Latin version Augustine had before him: affectabat, et tympanizabat ad ostia civitatis, et ferebatur in manibus suis, et procidebat ad ostia portae [He affected madness and drummed at the gates of the city and was carried on his own hands and fell down at the threshold of the gate]. Augustine, of course, knew that David is a type of Christ, and so applied each detail to him. He writes:

What does "affected" mean? It means he was full of affection. For what is as full of affection as the mercy of our Lord Jesus Christ who, seeing our weakness, in order to free us from endless death, took upon himself our temporal death with such great injury and disgrace. "And he drummed": because a drum is made by stretching skin across a wooden frame. Davids drumming symbolized that Christ was to be crucified. "He drummed at the gates of the city": because what are the "gates of the city" but our hearts, which we have closed against Christ, who from the drum of the cross has opened the hearts of us mortals. (Enar. In Ps 33(2), 2)

In a typological interpretation of the crossing of the Red Sea, applying it to Christian baptism, Augustine uses the same conceit in commenting on the verse: "Mary the prophetess, the sister of Aaron, took a drum in her hand, and all the women went forth after her with drums and dances," joining in the Canticle of Moses (Ex 15:20-21).

This is what Moses and the sons of Israel sang, what Mary the prophetess and the daughters of Israel with her sang, and this is what we, both men and women, both our spirit and our flesh, now sing. This is how we may fittingly understand the drum that Mary took up to harmonize with this canticle, for a drum is made by stretching flesh over wood, and it is from the cross that Christians learn how to sing the sweet song of grace. Baptism has made us humble by Gods gracious mercy and has destroyed the pride by which the enemy reigned over us, so that now anyone who boasts must boast in the Lord (1 Cor 1:31): "Let us sing to the Lord, for he is gloriously magnified: horse and rider he has thrown into the sea!" (Sermon 363, 4; PL 39, 1638)