Matthew Poole and continuators on Hosea 8:11

11 Because Ephraim hath made many altars to sin , altars shall be unto him to sin .

This refers to what follows.

Multiplyed either to many Idols, every one having his Altar, or multiplyed Altars in several places to the same Idol. They had many high places and Altars in all of them.

Both as acting against the Law of God which required but one Altar, and also these Altars were to sin, in that they were for Sacrifices to be offered on them to Idols. These persons did not intend them for sin, but their good intention did not, could not change the thing, 'twas sin however they intended.

Either those here erected, or those they shall find in Assyria, when they come Captives thither.

Either because forced in captivity to worship Assyrian Idols, and to attend their Altars and Sacrifices, or else by a just and dreadful judgment from God, delivering them over to their wilful blindness, and Idolatrous heart, since they would never be reclaim'd, nor taken off from sinful multiplying Altars, let them follow their own hearts, and set up what they will, much like that, Revel. 22.11. Or else thus, Altars shall be the occasion of his greater guilt and punishment, his Altars, i. e. his idolatrous worship shall be that sin that ruins him.