Bible Verses About Sieges: Frequently helped by allies

The next day Saul organized the troops into three divisions, and during the morning watch they invaded the camp of the Ammonites and slaughtered them, until the hottest part of the day. And the survivors were so scattered that no two of them were left together.

Then David and his men went to Keilah, fought against the Philistines, and carried off their livestock, striking them with a mighty blow. So David saved the people of Keilah.