Commentaries
32:15-20 What a change it is, to come down from the mount of communion with God, to converse with a wicked world. In God we see nothing but what is pure and pleasing; in the world nothing but what is sinful and provoking. That it might appear an idol is nothing in the world, Moses ground the calf to dust. Mixing this powder with their drink, signified that the backslider in heart should be filled with his own ways.
15-18. Moses turned, and went down from the mount—The plain, Er-Raheh, is not visible from the top of Jebel Musa, nor can the mount be descended on the side towards that valley; hence Moses and his companion, who on duty had patiently waited his return in the hollow of the mountain's brow, heard the shouting some time before they actually saw the camp.