John Gill's Bible Commentary Ver. 5. Then Rezin king of Syria, and Pekah son of Remaliah king of Israel, came up to Jerusalem to war , etc.] To fight with Ahaz, moved to it by the Lord, to chastise Ahaz for his idolatry, ( 2 Kings 15:37 Chronicles 28:5) but could not overcome him ; so as to take Jerusalem, and set up another king there, as their scheme was, ( Isaiah 7:5,) though they had both at other times got great advantages over him, and slew many of his people, and carried them captive, (see 2 Chronicles 28:5-8).
Matthew Henry Commentary
Verses 1-9 - Few and evil were the days of Ahaz. Those whose hearts condemn them will go any where in a day of distress, rather than to God. The sin wa its own punishment. It is common for those who bring themselves int straits by one sin, to try to help themselves out by another.
Original Hebrew אז227 יעלה5927 רצין7526 מלך4428 ארם758 ופקח6492 בן1121 רמליהו7425 מלך4428 ישׂראל3478 ירושׁלם3389 למלחמה4421 ויצרו6696 על5921 אחז271 ולא3808 יכלו3201 להלחם׃3898