(21) I took your sin . . . and I cast the dust thereof into the brook.--The stream from the rock in Horeb not only gave Israel drink, but bore away their "sin" upon its waters. "And that Rock was Christ." This identification of the sin with the material object is in harmony with the Law in Leviticus, where "sin" and "sin-offering"--"trespass" and "trespass offering"--are respectively denoted by a single word.

9:7-29 That the Israelites might have no pretence to think that God brought them to Canaan for their righteousness, Moses shows what a miracle of mercy it was, that they had not been destroyed in the wilderness. It is good for us often to remember against ourselves, with sorrow and shame, our former sins; that we may see how much we are indebted to free grace, and may humbly own that we never merited any thing but wrath and the curse at God's hand. For so strong is our propensity to pride, that it will creep in under one pretence or another. We are ready to fancy that our righteousness has got for us the special favour of the Lord, though in reality our wickedness is more plain than our weakness. But when the secret history of every man's life shall be brought forth at the day of judgment, all the world will be proved guilty before God. At present, One pleads for us before the mercy-seat, who not only fasted, but died upon the cross for our sins; through whom we may approach, though self-condemned sinners, and beseech for undeserved mercy and for eternal life, as the gift of God in Him. Let us refer all the victory, all the glory, and all the praise, to Him who alone bringeth salvation.And I took your sin, the calf which ye had made,.... Which was the object of their sin, which lay in making and worshipping it; see Isaiah 31:7.

and burnt it with fire, and stamped it; with his feet after it was burnt, to bring it into small pieces:

and ground it very small; or, as the Targum of Jonathan,"ground it in a mortar well;''the burnt and broken pieces:

even until it was as small as dust; being ground to powder, as in Exodus 32:20.

and I cast the dust thereof into the brook that descended out of the mount; and made the children of Israel to drink of it, as in the previously mentioned place; See Gill on Exodus 32:2; all this was done before the prayer for Aaron and the people.