Exodus 32:4 - 32:6
4 And he took this from their hand and fashioned it with a graving tool and made it into a molten calf; and they said, “These are your gods, O Israel, who brought you up from the land of Egypt.” 5 And Aaron looked and built an altar before it; and Aaron made a proclamation and said, “Tomorrow shall be a feast to Yahweh.” 6 So the next day they rose early and offered burnt offerings and brought peace offerings; and the people sat down to eat and to drink and rose up to play.