'Brethren' in the Bible

Seeing ye have purified your souls in obeying the truth through the Spirit unto unfeigned love of the brethren, see that ye love one another with a pure heart fervently:

Finally, be ye all of one mind, having compassion one of another, love as brethren, be pitiful, be courteous:

Whom resist stedfast in the faith, knowing that the same afflictions are accomplished in your brethren that are in the world.