What is the difference between the secret things and the things that are revealed?
The secret things are what God has not disclosed and therefore remain His own possession. The revealed things are what He has made known and given to His people. Once a secret is revealed, it is no longer secret; it must be believed and lived by.
Les explains that the secret things belong to the Lord our God, but the things which are revealed belong unto us. As soon as a secret is revealed, it is no longer a secret; it is to be believed, as the verse implies. Moses was writing to the children of Israel, and they had not had everything revealed to them at once. Once God laid out the Law, the tabernacle worship, the ritual, and the civil law, those things were no longer secret. God expected the Jew to believe it and live by it. Even the prophets, when they wrote, had no way of understanding what they wrote, because God had not revealed it in such a way that they could understand. Les also ties this to God dealing with time and things kept secret in time, then moves to Psalm 2 for review.