Because Ephraim has multiplied altars for sinning, They became for him altars for sinning.
It is then no superfluous repetition, when the Prophet says, that altars were multiplied in order to sin; and then, that altars would be for sin: for in the second clause, he speaks of the punishment which God would inflict on superstitious men. In the first clause, he shows that their good intentions were frivolous, and that they were greatly deceived, when at their pleasure they devised for themselves various forms of worship. This is one thing. Then it follows, There shall then be to them altars to sin; as they would not willingly repent, nor embrace salutary admonitions, God would at last really show how much he valued what they called their good intentions; for now a dreadful vengeance was at hand, which would prove to them, that in increasing altars, they did nothing else but increase sins. It then follows — 