Exode 24:12

And the Lord said to Mosheh, Ascend before Me at the mount, and I will there give thee the tables of stone on which I have set forth the rest of the words of the Law, and the six hundred and thirteen precepts which I have written for their instruction.

AND THE ETERNAL SAID UNTO MOSES: ‘COME UP TO ME INTO THE MOUNTAIN.’ This is the same command which He had said to him on the preceeding day [i.e., on the sixth of Sivan], Come up unto the Eternal; and Moses alone shall come near unto the Eternal, and now on the seventh day of Sivan He said additionally to him, and be there, and I will give thee the Tablets of stone etc., for Moses was to stay on the mountain until He would give him the Tablets of stone, and the law and the commandment. The expression which I have written refers back to the Tablets of stone; that thou mayest teach them relates to the law and the commandment. Thus the meaning of the verse is: “and I will give thee the Tablets of stone which I have written, and the law and the commandment that thou mayest teach them.” This is identical with what He said in the Book of Deuteronomy, And I will speak unto thee all the commandment, and the statutes, and the ordinances, which thou shalt teach them.
Rashi wrote: “Which I have written in the Tablets of stone. That thou mayest teach them, for all the six hundred and thirteen commandments are implicit in the Ten Commandments.” And Rabbi Abraham ibn Ezra commented: “The law, this refers to the first and second commandments; and the commandment refers to the other eight mentioned.” It is a comment of no value, since the verse in Deuteronomy mentioned above, And I will speak unto thee, etc. testifies that He is speaking about all the commandments. In accordance with the opinion of our Rabbis it is possible that the expression which I have written is a hint that the whole Torah was written before Him before the creation of the world, as I have mentioned at the beginning of the Book of Genesis.

אשר כתבתי, the tablets inscribed by G’d at the end of 40 days.

עלה אלי ההרה, to the top of the mountain. This was after he had already approached more closely than the people with him, as we have read in verse 2, ונגש משה לבדו “only Moses alone is to approach any closer.” Nonetheless, at that point he had not ascended the summit of the mountain. It was on this occasion, while they looked after Moses disappearing into the cloud forming a shroud around the mountain, that the “nobles” and the elders had the vision just described. This is what was meant in verse 17 with the words ומראה כבוד ה' כאש אוכלת בראש ההר, “and the manifestation of the glory of the Lord was similar to a consuming fire at the top of the mountain.” We find this formulation (ראש ההר) again during the giving of the Ten Commandments in 19,20.

והיה שם, stay there for an extended period. The root היה appears in this sense in Deuteronomy 10,5 ויהיו שם כאשר צוני, “they have remained there as G’d had commanded me.”

והתורה, “and the part which requires profound study,”

והמצוה, and the part of the Torah which primarily requires action in order to fulfill it.

אשר כתבתי, “which I (the Lord) have written.” If it had not been for the sin of the golden calf, the entire Torah would have been handed to the Jewish people (Moses) as a signed and sealed document just like the Tablets with the Ten Commandments. Moses alluded to this when he described the approach of G’d to Mount Sinai in Deuteronomy 33,2 ואתה מרבבות קודש מימינו אש דת למו , G’d was ready to hand us the whole Torah but the sin of the golden calf prevented this at that that time. Instead, Moses wrote down the Torah at G’d’s command (dictation). Moses is on record as having done this in Deuteronomy 34,27. In fact, Moses only brought the Tablets to within sight of the people in order to smash them before their eyes, so that they would understand what they had forfeited due to their disloyalty to G’d. This demonstration of Moses having smashed the Tablets was designed to shock the people into penitence.