פּירוש אויף שמות 24:4

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).

ושתים עשרה מצבה, “and 12 stone pillars;” this refers to G-d’s commandment to mark off the area at the bottom of Mount Sinai beyond which none of the people were allowed to approach. (19,12) 3 pillars in the east for the three tribes encamped there, three pillars in the south, the west and the north, as they were encamped also while in the desert. Some commentators say that Moses placed 12 stone pillars on the east on the altar as a symbol that all twelve tribes were completely content with maintaining the covenant with Hashem. We find a parallel to this in what the prophet Elijah did on Mount Carmel: ויקחו שתים עשרה אבנים למספר בני ישראל, “they took twelve stones to symbolize the twelve tribes of Israel.” (Kings I 18,31.)

FOR THE TWELVE TRIBES OF ISRAEL. As a witness, that all of them were satisfied with the establishment of the covenant.

וישכם בבקר AND ROSE UP EARLY IN THE MORNING — on the fifth of Sivan (cf. Rashi on Exodus 19:11) (Shabbat 88a).