“Third, [the doctors say] that marriage produces offspring, for that is the end and chief purpose of marriage. It is not enough, however, merely for children to be born, and so what they say about marriage excusing sin does not apply in this case. Heathen, too, bear offspring. But unfortunately it seldom happens that we bring up children to serve God, to praise and honor him, and want nothing else of them. People seek only heirs in their children, or pleasure in them; the serving of God finds what place it can. You also see people rush into marriage and become mothers and fathers before they know what the commandments are or can pray
But this at least all married people should know. They can do no better work and do nothing more valuable either for God, for Christendom, for all the world, for themselves, and for their children than to bring up their children well” (Luther’s Works, vol. 44, p.12-13).