Charles Ellicott Commentary Exodus 32:19

"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." — Exodus 32:19 (ASV)

And the dancing.— Hebrew, and dances. What Moses saw was "the calf" which had already been mentioned, and "dances" which had not been mentioned, but which were now going on after the usual fashion of idolatrous festivity. Such dancing among Eastern nations was uniformly of a lascivious character. .

He cast the tables out of his hands.—Compare to Deuteronomy 9:17. In righteous indignation, but perhaps with some revival of the hot temper which had led him astray in his younger days (Exodus 2:12).