'Brother' in the Bible

Paul, a called apostle of Jesus Christ, by God's will, and Sosthenes the brother,

But now I have written to you, if any one called brother be fornicator, or avaricious, or idolater, or abusive, or a drunkard, or rapacious, not to mix with him; with such a one not even to eat.

But brother prosecutes his suit with brother, and that before unbelievers.

But as to the rest, I say, not the Lord, If any brother have an unbelieving wife, and she consent to dwell with him, let him not leave her.

For the unbelieving husband is sanctified in the wife, and the unbelieving wife is sanctified in the brother; since otherwise indeed your children are unclean, but now they are holy.

But if the unbeliever go away, let them go away; a brother or a sister is not bound in such cases, but God has called us in peace.

and the weak one, the brother for whose sake Christ died, will perish through thy knowledge.

Wherefore if meat be a fall-trap to my brother, I will eat no flesh for ever, that I may not be a fall-trap to my brother.

Now concerning the brother Apollos, I begged him much that he would go to you with the brethren; but it was not at all his will to go now; but he will come when he shall have good opportunity.