In the final speeches of Moses certain themes recur that a kind of undertone but crucial cores of being a good Jew and a good person. The two ought to go together. It is clear that he regards the Sinai Revelation as the will of God for His people. The constitution is at the core of Jewish life. But at the same time, he keeps returning to the failure of the Israelites to remain true to God. The failure of humans to live up to their ideals.
But loyalty to God, in his view should come with two inter-human obligations. The first is to mankind in general.
“You should keep these commandments for it is this that will distinguish you as wise and understanding in the eyes of other peoples, who will hear about these laws and say that they can only be the indication that this people is wise and understanding” (Chapter 4.6).
In other words, it matters what other people think. If we are told to destroy the pagan Canaanite there are plenty of other nations and peoples in the world and our task it to set an example. But if we are seen as petty, simple, narrow minded and reduce our laws to ridiculous extremes, or refuse to make changes that equity demands, then people will only look at us and laugh.
The other phrase is “Keep the laws of God, His principles and statutes and rules which he has commanded you. And you should do what is right and good in the eyes of God” (Chapter 6.17/18).
Now if it were enough just to keep the commandments of God, we would not need any additional statement. Unless this was adding something on to the commandments. And I believe it does. It tells us there are certain universal values of good and just that are in addition to the rules and regulations. Without them the whole edifice is in danger of disintegration.