Adam Clarke on Isaiah 14:28

In the year that king Ahaz died was this burden - Uzziah had subdued the Philistines, 2Chr 26:6, 2Chr 26:7; but, taking advantage of the weak reign of Ahaz, they invaded Judea, and took, and held in possession, some cities in the southern part of the kingdom. On the death of Ahaz, Isaiah delivers this prophecy, threatening them with the destruction that Hezekiah, his son, and great-grandson of Uzziah, should bring upon them: which he effected; for "he smote the Philistines, even unto Gaza, and the borders thereof," 2Kgs 18:8. Uzziah, therefore, must be meant by the rod that smote them, and by the serpent from whom should spring the flying fiery serpent, Isa 14:29, that is, Hezekiah, a much more terrible enemy than even Uzziah had been.

The Targum renders the twenty-ninth verse in a singular way. "For, from the sons of Jesse shall come forth the Messiah; and his works among you shall be as the flying serpent."