In the church, there is no longer any distinction between Jew or Gentile, male or female, slave or free, because all are united equally in Christ to form his Body, the church.
"There are many different metaphors in the Bible that help us understand who we are as a people of God, but none more to be treasured or more to be meditated upon and applied than the body of Christ. When the Bible says that we are the body of Christ, the metaphor begins with a picture of Jesus as the head of the body. Meaning this, he is the incarnate Lord.
He is the one who has literally come from Heaven into this world, taking a body unto himself. In his incarnate life, Jesus never ceased being God, but he took fully to himself our humanity, and now that he has ascended after his crucifixion and resurrection, his body in our midst, the way by which he does his Kingdom work, he reveals his commitment to make all things new is through literally his body. Men and women that he died for, that he now has called forth to live in union with himself. And so the body of Christ celebrates that image, that metaphor. It celebrates that we belong to Jesus, not ourselves, that we have been engrafted, we have been birthed literally into his heart.
And we are called and gifted and commissioned to live out under his headship with his heart. We're to extend his tear-wiping hand into the culture. We're to be the means by which he will begin to demonstrate how he's making all things new. So, the body of Christ is much more than just a metaphor. It's literally who we have been constituted by the truth of the Gospel, by the end-dwelling Spirit, and by the gifts we've been given. It should humble us, and gladden us. It should focus us on how we live in the light of day when he comes back to finish making all things new.
The Ultimate Membership
As has been shown, the Body of Christ is not a building or specific denomination, but rather is comprised of believers of all time since Pentecost. The Holy Spirit plays a major part in joining individuals to Christ through indwelling, baptism, and sealing.
Only those who have been baptized by the Holy Spirit, i.e., saved by grace through faith, can join the church. Scripture distinctly uses the phrase “Body of Christ” to demonstrate the identity and oneness of believers in Christ.”
~ from Christianity.com, author Sophia Bricker