John Gill Commentary 2 Chronicles 32:8

"with him is an arm of flesh; but with us is Jehovah our God to help us, and to fight our battles. And the people rested themselves upon the words of Hezekiah king of Judah." — 2 Chronicles 32:8 (ASV)

With him is an arm of flesh
Only weak, frail, mortal men, not at all to be feared; nothing in comparison of the Lord:

but with us is the Lord our God, to help us, and to fight our battles ;
who is the Lord God Almighty, who has the host of heaven at his command, and with whom all the inhabitants of the earth are as nothing; the Targum is, ``the Word of the Lord our God is for us to help us, and fight our battles:''

and the people rested themselves upon the words of Hezekiah king of
Judah ;
not upon his bare words, but on what was contained in them, on the strength and power of the Lord God he assured them was on their side; they believed what he said to be true, and trusted in the Lord that he would save them.