'Brethren' in the Bible

Then Abner called to Joab, and said, Shall the sword devour for ever? knowest thou not that it will be bitterness in the latter end? how long shall it be then, ere thou bid the people return from following their brethren?

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

Then was Abner very wroth for the words of Ishbosheth, and said, Am I a dog's head, which against Judah do shew kindness this day unto the house of Saul thy father, to his brethren, and to his friends, and have not delivered thee into the hand of David, that thou chargest me to day with a fault concerning this woman?

Whereas thou camest but yesterday, should I this day make thee go up and down with us? seeing I go whither I may, return thou, and take back thy brethren: mercy and truth be with thee.

Ye are my brethren, ye are my bones and my flesh: wherefore then are ye the last to bring back the king?

And, behold, all the men of Israel came to the king, and said unto the king, Why have our brethren the men of Judah stolen thee away, and have brought the king, and his household, and all David's men with him, over Jordan?