Deuteronomy 4:10

Specially the day that thou stoodest before the LORD thy God in Horeb, when the LORD said unto me, Gather me the people together, and I will make them hear my words, that they may learn to fear me all the days that they shall live upon the earth, and that they may teach their children.

The day that thou stoodest before the Lord ... in Horeb. The delivery of the law from Sinai was an era never to be forgotten in the history of Israel. Some of those whom Moses was addressing had been present, though very young; while the rest were federally represented by their parents, who in their name and for their interest entered into the national covenant.