There are various reasons why parents neglect this duty. In the first place, there are some who lack the goodness and decency to do it, even if they had the ability. Instead, like the ostrich [Job 39:14–16], they deal cruelly with their young. They are content to have laid the eggs and brought children into the world; beyond this they will do nothing more. But these children are supposed to live among us and with us in the community. How then can reason, and especially Christian charity, allow that they grow up uneducated, to poison and pollute the other children until at last the whole city is ruined, as happened in Sodom and Gomorrah [Gen. 19:1–25], and Gibeah [Judges 19–20], and a number of other cities?
In the second place, the great majority of parents unfortunately are wholly unfitted for this task. They do not know how children should be brought up and taught, for they themselves have learned nothing but how to care for their bellies. It takes extraordinary people to bring children up right and teach them well.
In the third place, even if parents had the ability and desire to do it themselves, they have neither the time nor the opportunity for it, what with their other duties and the care of the household. Necessity compels us, therefore, to engage public schoolteachers for the children—unless each one were willing to engage his own private tutor. But that would be too heavy a burden for the common man, and many a promising boy would again be neglected on account of poverty. Besides, many parents die, leaving orphans, and if we do not know from experience how they are cared for by their guardians it should be quite clear from the fact that God calls himself Father of the fatherless [Ps 68:5], of those who are neglected by everyone else. Then too there are others who have no children of their own, and therefore take no interest in the training of children. (Luther’s Works, v. 45 p. 354-355).