Therefore God has also most richly blessed this estate above all others, and, in addition has bestowed on it andwrapped up in it everything in the world, to the end that this estate might be well and richly provided for. Married life is therefore no jest or presumption; but it is an excellent thing and a matter of divine seriousness. For it is of the highest importance to Him that persons be raised who may serve the world and promote the knowledge of God, godly living, and all virtues, to fight against wickedness and the devil.
Martin Luther (1483-1546), The Large Catechism
But the greatest good in married life, that which makes all suffering and labour worth while, is that God grants offspring and commands that they be brought up to worship and serve him. In all the world this is the noblest and most precious work, because to God there can be nothing dearer than the salvation of souls. Now since we are all duty bound to suffer death, if need be, that we might bring a single soul to God, you can see how rich the estate of marriage is in good works. God has entrusted to its bosom souls begotten of its own body, on whom it can lavish all manner of Christian works. Most certainly father and mother are apostles, bishops, and priests to their children, for it is they who make them acquainted with the gospel. In short, there is no greater or nobler authority on earth than that of parents over their children, for this authority is both spiritual and temporal. whoever teaches the gospel to another is truly his apostle and bishop. Mitre and staff and great estates indeed produce idols, but teaching the gospel produces apostles and bishops. See therefore how good and great is God’s work and ordinance!
Luther, Sermon on Married Life