John Piper has written a helpful post at the Desiring God blog titled "Why Require Unregenerate Children to Act Like They’re Good?"
Piper answers the question in the title of his post with three points.
- For children, external, unspiritual conformity to God’s commanded patterns of behavior is better than external, unspiritual non-conformity to those patterns of behavior.
- Requiring obedience from children in conformity with God’s will confronts them with the meaning of sin in relation to God, the nature of their own depravity, and their need for inner transformation by the power of grace through the gospel of Christ.
- The marks of devotion, civility, and manners (“please,” “thank you,” and good eye contact) are habits that, God willing, are filled later with grace and become more helpful ways of blessing others and expressing a humble heart.
I think many parents with young children struggle with this issue. Piper offers wise counsel so make sure to read the entire post.