Albert Barnes Commentary Hosea 8:11

"Because Ephraim hath multiplied altars for sinning, altars have been unto him for sinning." — Hosea 8:11 (ASV)

Because Ephraim has made many altars to sin, altars shall indeed be to him for sin—that is, they shall be proven to him to be so by the punishment which they shall bring 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 show and pretenses 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 on them offer sacrifices for the expiation of their sins and the appeasing of God.

They endeavored to unite their own self-will and the outward service of God. In that 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 pretense whatever, was to sin. So then, as many altars as they reared, so often did they repeat their sin, and this sin would be their only fruit.

They were to be so, 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).