Exodus 32:15-19

Then Moses turned and went down from the mountain with the two tablets of the testimony in his hand, tablets which were written on both sides; they were written on one side and the other.

The tablets were God’s work, and the writing was God’s writing engraved on the tablets.

Now when Joshua heard the sound of the people as they shouted, he said to Moses, “There is a sound of war in the camp.”

But he said, “It is not the sound of the cry of victory, Nor is it the sound of the cry of defeat; But I hear the sound of singing.” Moses’ Anger

And it came about, as soon as Moses approached the camp, that he saw the calf and the people dancing; and Moses’ anger burned, and he threw the tablets from his hands and shattered them to pieces at the foot of the mountain.