God wrote the Law on a second set of stone tablets.
With intercession, punishment, forgiveness, and restoration complete, GOD told Moses to cut out a new set of stone tablets so that He could rewrite the Law.
1 Now the Lord said to Moses, “Cut two tablets of stone like the first ones, and I will write on these tablets the words that were on the first tablets you broke. 2 So be ready in the morning to come up on Mount Sinai and to present yourself to Me there on top of the mountain. 3 But no man shall come up with you, and let no man be seen throughout all the mountain; let neither sheep nor oxen feed before that mountain.” 4 So he cut two tablets of stone like the first ones. Then Moses rose early in the morning and went up to Mount Sinai as the Lord commanded him; and he took in his hand the two tablets of stone.
27 Again the Lord said to Moses, “Write these words for yourself, for according to these words I established a covenant with you and with Israel.” 28 So he was there with the Lord forty days and forty nights; he neither ate bread nor drank water. He wrote on the tablets the words of the covenant, the Ten Commandments.
(Exodus 34:1-4, 27-28 OSB)
The stone tablets served as an important reminder for Israel of the ten commandments, the Law, and GOD's personal delivery of them to Israel. They were proof of Israel's past.