And the LORD said unto Moses, Write thou these words: for after the tenor of these words I have made a covenant with thee and with Israel.

Jamieson-Fausset-Brown Bible Commentary

27, 28. And the Lord said unto Moses, Write thou these words-that is, the ceremonial and judicial injunctions comprehended above (Ex 34:11-26); while the rewriting of the ten commandments on the newly prepared slabs was done by God Himself (compare De 10:1-4).

Matthew Henry's Concise Commentary

34:18-27 Once a week they must rest, even in ploughing time, and in harvest. All worldly business must give way to that holy rest; even harvest work will prosper the better, for the religious observance of the sabbath day in harvest time. We must show that we prefer our communion with God, and our duty to him, before the business or the joy of harvest. Thrice a year they must appear before the Lord God, the God of Israel. Canaan was a desirable land, and the neighbouring nations were greedy; yet God says, They shall not desire it. Let us check all sinful desires against God and his glory, in our hearts, and then trust him to check all sinful desires in the hearts of others against us. The way of duty is the way of safety. Those who venture for him never lose by him. Three feasts are here mentioned: 1. The Passover, in remembrance of the deliverance out of Egypt. 2. The feast of weeks, or the feast of Pentecost; added to it is the law of the first-fruits. 3. The feast of in-gathering, or the feast of Tabernacles. Moses is to write these words, that the people might know them better. We can never be enough thankful to God for the written word. God would make a covenant with Israel, in Moses as a mediator. Thus the covenant of grace is made with believers through Christ.