Many altars to sin - Though it does not appear that the Jews in Babylon were obliged to worship the idols of the country, except in the case mentioned by Daniel, yet it was far otherwise with the Israelites in Assyria, and the other countries of their dispersion. Because they had made many altars to sin while they were in their own land, they were obliged to continue in the land of their captivity a similar system of idolatry against their will. Thus they felt and saw the evil of their idolatry, without power to help themselves.
Because Ephraim hath made many altars to sin, altars shall indeed be unto him to sin - that is, they shall be proved to him to be so, by the punishment which they shall draw upon him. The prophet had first shown them their folly in forsaking God for the help of man; now he shows them the folly of attempting to “secure themselves by their great shew and pretences of religion and devotion in a false way.” God had appointed “one” altar at Jerusalem. There He willed the sacrifices to be offered, which He would accept. To multiply altars, much more to set up altars against the one altar, was to multiply sin. Hosea charges Israel elsewhere with this multiplying of altars, as a grievous sin. “According to the multitude of his fruit, he hath increased altars. Their altars are as heaps in the furrows of the field” Hosea 10:1; Hosea 12:11. They pretended doubtless, that they did it for a religious end, that they might thereon offer sacrifices for the expiation of their sins and appeasing of God. They endeavored to unite their own selfwill and the outward service of God. Therein they might deceive themselves; but they could not deceive God. He calls their act by its true name. To make altars at their own pleasure and to offer sacrifices upon them, under any pretence whatever, was to sin. So then, as many altars as they reared, so often did they repeat their sin; and this sin should be their only fruit. They should be, but only for sin. So God says of the two calves, “This thing became a sin” 1 Kings 12:30, and of the indiscriminate consecration of priests (not of the family of Aaron), “This thing became sin unto the house of Jeroboam, even to cut it off and to destroy it from the face of the earth” 1 Kings 13:33-34.