Charles Ellicott Commentary Exodus 34:1-4

"And Jehovah said unto Moses, Hew thee two tables of stone like unto the first: and I will write upon the tables the words that were on the first tables, which thou brakest. And be ready by the morning, and come up in the morning unto mount Sinai, and present thyself there to me on the top of the mount. And no man shall come up with thee; neither let any man be seen throughout all the mount; neither let the flocks nor herds feed before that mount. And he hewed two tables of stone like unto the first; and Moses rose up early in the morning, and went up unto mount Sinai, as Jehovah had commanded him, and took in his hand two tables of stone." — Exodus 34:1-4 (ASV)

Before the covenant could be formally reestablished, before Israel could be replaced in the position forfeited by the idolatry of the golden calf, it was necessary that the conditions on which God consented to establish His covenant with them should be set forth afresh. Moses had asked for the return of God’s favour, but had said nothing of these conditions.

It is God who insists on them. Hew thee two tables. The moral law must be delivered afresh—delivered in its completeness—exactly as at the first (Exodus 34:1), and even the ceremonial law must be reimposed in its main items (Exodus 34:12–26), or no return to favour is possible. Hence Moses is summoned once more to the top of Sinai, where the Law is to be delivered afresh to him, and is ordered to bring with him tables of stone like the former ones, to receive their written contents from God’s hand.