1 Kings 11:16

16 Joab and all the Israelites stayed there for six months, until they had destroyed all the men in Edom.

Read 1 Kings 11:16 Using Other Translations

(For six months did Joab remain there with all Israel, until he had cut off every male in Edom:)
(for Joab and all Israel remained there six months, until he had cut off every male in Edom).
Joab and the army of Israel had stayed there for six months, killing them.