Exodus 32:15-16, 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.

It came about, as soon as Moses came near the camp, that he saw the calf and the dancing; and Moses’ anger burned, and he threw the tablets from his hands and shattered them at the foot of the mountain.