He built. — He it was that built (pronoun emphatic). He “built,” i.e., restored and beautified. The same statement occurs in 2 Kings 15:35.
The high gate. — Rather, the upper gate; i.e., the northern gate of the inner or upper court (Ezekiel 9:2). The north being the holy quarter (Isaiah 14:13; Psalms 48:2), the north gate would be the principal entrance.
And on the wall of Ophel he built much. — The southern slope of the Temple hill was called the Ophel, i.e., “the mound.” Its wall would be the line of fortifications connecting Zion with Moriah, on which Uzziah had already laboured (2 Chronicles 26:9), with the same object of securing the city against attacks from the south and east. Neither this detail nor the next three verses are found in the parallel account. The style and contents of the passage indicate a good ancient source.
Much. — Larôb, “to much;” one of the chronicler’s favourite words.