“went up on Mount Sinai.” This is Moses’ seventh and final time up Mount Sinai before Israel left the area. On this trip, Moses took two stone tablets that he had chiseled out of stone to replace the ones he had broken that God had made. God wrote on the tablets (Exod. 34:28), but Moses had to chisel them out of rock and bring them to God.
As with Moses’ fifth time up Mount Sinai, Moses was there for forty days and forty nights (Exod. 34:28), but this time when Moses was gone the Israelites at the bottom of the mountain obeyed God and waited patiently for Moses to come down. Then, when Moses finally did come down, his face radiated (Exod. 34:29).
[For more information on Moses’ seven trips up Mount Sinai, see commentary on Exod. 19:3].