4:1-23 The power and love of God to Israel are here made the ground and reason of a number of cautions and serious warnings; and although there is much reference to their national covenant, yet all may be applied to those who live under the gospel. What are laws made for but to be observed and obeyed? Our obedience as individuals cannot merit salvation; but it is the only evidence that we are partakers of the gift of God, which is eternal life through Jesus Christ, Considering how many temptations we are compassed with, and what corrupt desires we have in our bosoms, we have great need to keep our hearts with all diligence. Those cannot walk aright, who walk carelessly. Moses charges particularly to take heed of the sin of idolatry. He shows how weak the temptation would be to those who thought aright; for these pretended gods, the sun, moon, and stars, were only blessings which the Lord their God had imparted to all nations. It is absurd to worship them; shall we serve those that were made to serve us? Take heed lest ye forget the covenant of the Lord your God. We must take heed lest at any time we forget our religion. Care, caution, and watchfulness, are helps against a bad memory.

3, 4. Your eyes have seen what the Lord did because of Baal-peor … the Lord thy God hath destroyed them from among you—It appears that the pestilence and the sword of justice overtook only the guilty in that affair (Nu 25:1-9) while the rest of the people were spared. The allusion to that recent and appalling judgment was seasonably made as a powerful dissuasive against idolatry, and the fact mentioned was calculated to make a deep impression on people who knew and felt the truth of it.