God is a giver! He gives membership!

“So we, though many, are one body in Christ, and individually members one of another.” (Rom. 12:5 ESV)

Individual members

“Now you are the body of Christ and individually members of it.” (1 Cor. 12:27 ESV)

All made to drink of one Spirit 

“For in one Spirit we were all baptized into one body—Jews or Greeks, slaves or free—and all were made to drink of one Spirit.” (2 Cor. 12:13 ESV)

Members of the household of God

“So then you are no longer strangers and aliens, but you are fellow citizens with the saints and members of the household of God, built on the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone, in whom the whole structure, being joined together, grows into a holy temple in the Lord. In him you also are being built together into a dwelling place for God by the Spirit.” (Eph. 2:19-22 ESV)

Therefore…

“If one member suffers, all suffer together; if one member is honored, all rejoice together.” (1 Cor. 12:26 ESV)

“So then, as we have opportunity, let us do good to everyone, and especially to those who are of the household of faith.” (Gal. 6:10 ESV)

“A new commandment I give to you, that you love one another: just as I have loved you, you also are to love one another” (John 13:33