Charles Ellicott Commentary Joshua 10:19

"but stay not ye; pursue after your enemies, and smite the hindmost of them; suffer them not to enter into their cities: for Jehovah your God hath delivered them into your hand." — Joshua 10:19 (ASV)

Smite the hindmost of them. —See Deuteronomy 25:18, the only other place where the same Hebrew verb occurs.

For the Lord your God has delivered them into your hand. —It is worthwhile to observe that the command given to Israel to exterminate the Canaanites, though perfectly general, is nevertheless limited as to time and circumstances by this very condition, in Deuteronomy 7:1-2 and Joshua 10:1-2, when the Lord your God shall bring you in, ... and has cast out ... before you ... seven nations, and when the Lord your God shall deliver them before you, you shall smite them and utterly destroy them.

Again, Joshua 10:16, You shall consume all the people whom the Lord your God shall deliver you, and Joshua 10:22, The Lord your God will put out those nations before you by little and little; you may not consume them at once.

The extermination of each particular army or nation was to be determined (as to time and circumstances) by the mandate of Jehovah, whose guidance Israel must follow on all occasions.

The present occasion was one for pursuit and slaughter without respite or delay. But though the army, as an army, was annihilated, a remnant of fugitives escaped into fortified places (Joshua 10:20).