1 Kings 11:16

for six months Not too long a time to be spent in establishing garrisons which might hold the land.

with all Israel This like the last verse must be understood only of such forces as were engaged in this war. David with a sufficient bodyguard would retire northward, through a country all his own, and where no greater force was needed, leaving Joab and the bulk of the host to complete the arrangements for the holding of Edom.