Adam Clarke on Proverbs 19:18

Let not thy soul spare for his crying - This is a hard precept for a parent. Nothing affects the heart of a parent so much as a child's cries and tears. But it is better that the child may be caused to cry, when the correction may be healthful to his soul, than that the parent should cry afterwards, when the child is grown to man's estate, and his evil habits are sealed for life.