Albert Barnes Commentary 2 Kings 18:7

"And Jehovah was with him; whithersoever he went forth he prospered: and he rebelled against the king of Assyria, and served him not." — 2 Kings 18:7 (ASV)

The Lord was with him - This phrase is very emphatic and had not been said of any king since David. The general prosperity of Hezekiah is set forth at some length by the author of Chronicles (2 Chronicles 32:23, 27-29).

His great influence among the nations bordering the northern kingdom was the cause of Sennacherib's first expedition against him. This occurred because the Ekronites had expelled an Assyrian viceroy from their city and delivered him to Hezekiah for safekeeping. This initial expedition did not long precede the one mentioned in 2 Kings 18:13, which took place toward the end of Hezekiah’s long reign.