And Moses wrote all the words of the Lord: and rising in the morning he built an altar at the foot of the mount, and twelve titles according to the twelve tribes of Israel.

“ויכתב משה AND MOSES WROTE [ALL THE WORDS OF THE LORD] — from בראשית up to (but not including) the account of the Giving of the Torah and he wrote down the commandments that were given to them in Marah (cf. Mekhilta on Exodus 19:10). וישכם בבקר AND ROSE UP EARLY IN THE MORNING — on the fifth of Sivan (cf. Rashi on Exodus 19:11) (Shabbat 88a).”

“And Moses wrote all the words of the Lord,.... Jarchi says, all from the creation, to the giving of the law, and the commands at Marah; but though these were written by him, yet not at this time; but as Aben Ezra more truly observes, what are mentioned in this "parashah", or section, or what is contained in the two preceding chapters, he not only related to them from his memory, but he wrote them in a book, which is after mentioned, that they might be seen and read hereafter; for these were not the ten commands, they were written as well as spoken by the Lord himself, but the judicial laws before mentioned: and rose up early in the morning: not on the fifth of Sivan, as Jarchi, the day before the giving of the law, but on the eighth of that month, two days after it: and built an altar under the hill: under Mount Sinai, about the place where the bounds were set, beyond which the people were not to go: and twelve pillars, according to the twelve tribes of Israel: to answer to them, and which were to represent them, as seems by the following account; these probably were made of marble stone, of which Mount Sinai consisted, and of which there was plenty thereabout.”

“Moses wrote all the words of the Lord - After the people had promised obedience, (Exo 24:3), and so entered into the bonds of the covenant, "it was necessary," says Calmet, "to draw up an act by which the memory of these transactions might be preserved, and confirm the covenant by authentic and solemn ceremonies." And this Moses does. 1. As legislator, he reduces to writing all the articles and conditions of the agreement, with the people's act of consent. 2. As their mediator and the deputy of the Lord, he accepts on his part the resolution of the people; and Jehovah on his part engages himself to Israel, to be their God, their King, and Protector, and to fulfill to them all the promises he had made to their fathers. 3. To make this the more solemn and affecting, and to ratify the covenant, which could not be done without sacrifice, shedding and sprinkling of blood, Moses builds an altar, probably of turf, as was commanded, Exo 20:24, and erects twelve pillars, no doubt of unhewn stone, and probably set round about the altar. The altar itself represented the throne of God; the twelve stones, the twelve tribes of Israel. These were the two parties, who were to contract, or enter into covenant, on this occasion.”