And king Ahaz went to Damascus to meet Tiglathpileser king of Assyria, and saw an altar that was at Damascus: and king Ahaz sent to Urijah the priest the fashion of the altar, and the pattern of it, according to all the workmanship thereof. Ahaz went to Damascus - He had received so much help on the defeat of Rezin, that he went to Damascus to meet the king of Assyria, and render him thanks.
Ahaz sent to Urijah the priest the fashion of the altar - This was some idolatrous altar, the shape and workmanship of which pleased Ahaz so well that he determined to have one like it at Jerusalem. For this he had no Divine authority, and the compliance of Urijah was both mean and sinful. That Ahaz did this for an idolatrous purpose, is evident from 2 Chronicles 28:21-25 : "For he sacrificed to the gods of Damascus; - and he said, Because the gods of the kings of Syria help them, I will sacrifice to them, that they may help me. And he made high places to burn incense to other gods in every city of Judah."