The ever popular verse:
Train up a child in the way HE will go and when HE is old HE will not depart from it. (Proverbs 22:6)
A lot of people think that means to keep your kids in church and when they are old, they'll still go.(I've actually heard them say this.) If that's what it means, then the Bible is a lie. God doesn't lie, so that's not what it means!
It means to guide your child to go the direction that he is wired. How interesting is that? God has wired each of us differently. If we learn in the way that we are wired, we'll stick with it!
Barnes' Notes on the Bible
Train - Initiate, and so, educate.
The way he should go - Or, according to the tenor of his way, i. e., the path especially belonging to, especially fitted for, the individual's character. The proverb enjoins the closest possible study of each child's temperament and the adaptation of "his way of life" to that.
For more commentaries: Proverbs 22:6