The child's question indicates that instruction has already been given. After all, Moses commanded them: You shall teach them [that is, God’s words] diligently to your children. Talk about them constantly when you are at home, when you walk along the road, when you lie down, and when you get up
(Deuteronomy 6:7). The point is that the parents' speech provokes questions from the children. A good story naturally provokes reactions. The listener is made curious about the reason for all the instructions that have been communicated. Why all these laws and rules? It is striking that the child speaks of the Lord our God.
He has understood that he belongs, that he is a covenant child. This is a fitting discovery, because the Lord thinks in terms of generations. Abraham heard this from the Lord even before he became a father: I will establish an everlasting covenant with you and with your descendants throughout your generations. I will be your God and the God of your offspring after you
(Genesis 17:7; see also Acts 2:39; 1 Corinthians 7:14). Infant baptism is rightly based on this promise.
20 “When your son asks you in time to come, ‘What is the meaning of the testimonies and the statutes and the rules that the LORD our God has commanded you?’