John Gill Commentary Joshua 10:42

"And all these kings and their land did Joshua take at one time, because Jehovah, the God of Israel, fought for Israel." — Joshua 10:42 (ASV)

And all these kings, and their land, did Joshua take at one
time
Not in one day, but in a very short time, in a few days, as the history clearly shows:

because the Lord God of Israel fought for Israel ;
which is the true reason of such quick dispatch being made, otherwise in all probability much longer time must have been consumed in subduing them. The Targum is, ``because the Lord God of Israel fought by his Word for Israel.''