'Brethren' in the Bible

Then Abner called to Joab, “Must the sword devour forever? Do you not know that it will be bitter in the end? How long [will it be] before you tell the people to stop pursuing their brothers?”

Joab said, “As God lives, if you had not spoken, then the people certainly would have stopped pursuing their brothers in the morning.”

You came only yesterday, so should I make you wander with us today while I go where I will? Return and take your brothers back with you also. May lovingkindness and faithfulness be with you.”