And when the king came from Damascus, the king viewed the altar. Then the king drew near to the altar and went up on it
Though Ahaz had himself sacrificed in high places, on hills, and under every green tree (Kg2 16:4), yet God's altar had hitherto continued in its place and in use, and the king's burnt-offering and his meat-offering (Kg2 16:15) had been offered upon it by the priests that attended it; but here we have it taken away by wicked Ahaz, and another altar, an idolatrous one...
Commenting on 2 Kings 16:10-16
And he burnt his burnt offering, and his meat offering,.... Which went together according to the law of God, and was imitated by the Heathens: and poured his drink offering; a libation of wine, as probably it was, like what they used according to the Levitical law: and sprinkled the blood of his peace offerings upon the altar; as used according to the same law...
And when the king was come from Damascus, the king saw the altar: and the king approached to the altar, and offered thereon. (h) Either offerings for peace or prosperity, or thanksgiving as in or else meaning the morning and evening offering, and thus he contemned the means and the altar which God had commanded by Solomon, to serve God after his own fantasy.