"When King Ahaz went to Damascus to meet Tiglath-pileser king of Assyria, he saw the altar that was at Damascus. And King Ahaz sent to Uriah the priest a model of the altar, and its pattern, exact in all its details” (16:10). Ahaz was one of Judah’s worst kings; he even sacrificed his own sons (v3). While making an alliance with Assyria, he visited Damascus and became obsessed with the pagan altar there. He installed a copy in the Temple and used it for sacrifices instead of the holy altar consecrated by Solomon.
We become what we admire and what we worship. Ahaz admired a pagan altar, and he eventually imitated the “despicable practices” of the nations (16:3).