Not through rash anger, but by Divine instinct, partly to punish their idolatry with so great a loss, and partly to show that the covenant made between God and them, so much to their advantage, which was contained in those tables, was by their sin broken, and now of none effect, and not to be renewed but by bitter repentance.
Related Commentaries of Exodus 32:19
Exodus 32:19
19 And it came to pass, as soon as he came nigh unto the camp, that he saw the calf, and the dancing: and Moses' anger waxed hot, and he cast the tables out of his hands, and brake them beneath the mount.