St. Augustine on childless sex

“You [Manicheans] make your Auditors adulterers of their wives when they take care lest the women with whom they copulate conceive. They take wives according to the laws of matrimony by tablets announcing that the marriage is contracted to procreate children; and then, fearing because of your law [against childbearing] . . . they copulate in a shameful union only to satisfy lust for their wives. They are unwilling to have children, on whose account alone marriages are made. How is it, then, that you are not those prohibiting marriage, as the Apostle predicted of you so long ago [1 Tim. 4:1-4], when you try to take from marriage what marriage is? When this is taken away, husbands are shameful lovers, wives are harlots, bridal chambers are brothels, fathers-in-law are pimps”

Augustine, 354-430, Against Faustus

John Calvin on Birth Control

“The voluntary spilling of semen outside of intercourse between man and woman is a monstrous thing. Deliberately to withdraw from coitus in order that semen may fall on the ground is doubly monstrous. For this is to extinguish the hope of the race and to kill before he is born the hoped-for offspring.” — John Calvin