After the warning of what not to do—that is, to forget the Lord—Moses's speech now turns to what should be done: the people are to show reverence for the Lord, serve him wholeheartedly, and swear by his name alone. These words echo the first three precepts of the Ten Commandments, which Moses had just reiterated to the people (Deuteronomy 5:7–11). A deep respect for the Lord must be evident in everything they do in the magnificent Promised Land. This conscious choice will be valuable for generations to come (see Deuteronomy 4:7–8; see also Deuteronomy 6:20–21).
It is significant that Jesus, when he was being tempted, refers back to these words of Moses. When the devil shows him the kingdoms of the world in all their splendour and then says that he will give them to Jesus if he bows down and worships him, Jesus answers, Be gone, Satan! For it is written 'you shall worship the Lord your God and him only shall you serve'
(Matthew 4:10). For him, Scripture has absolute authority. If this holds true for Jesus, it certainly does for us.
13 It is the LORD your God you shall fear. Him you shall serve and by his name you shall swear.