Heidelberg Catechism · 1563

Q55. What do you understand by the communion of saints?

First, that believers, all and everyone, as members of Christ have communion with Him and share in all His treasures and gifts. Second, that everyone is duty-bound to use his gifts readily and cheerfully for the benefit and well-being of the other members.
Answer · Heidelberg Catechism

Scripture proofs

  1. [1]
    Romans 8:32

    He that spared not his own Son, but delivered him up for us all, how shall he not with him also freely give us all things?

    1 Corinthians 6:17

    But he that is joined unto the Lord is one spirit.

    1 Corinthians 12:4-7

    Now there are diversities of gifts, but the same Spirit. And there are differences of administrations, but the same Lord. And there are diversities of operations, but it is the same God which worketh all in all. …

    1 Corinthians 12:12-13

    For as the body is one, and hath many members, and all the members of that one body, being many, are one body: so also is Christ. For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.

    1 John 1:3

    That which we have seen and heard declare we unto you, that ye also may have fellowship with us: and truly our fellowship is with the Father, and with his Son Jesus Christ.

  2. [2]
    Romans 12:4-8

    For as we have many members in one body, and all members have not the same office: So we, being many, are one body in Christ, and every one members one of another. Having then gifts differing according to the grace that is given to us, whether prophecy, let us prophesy according to the proportion of faith; …

    1 Corinthians 12:20-27

    But now are they many members, yet but one body. And the eye cannot say unto the hand, I have no need of thee: nor again the head to the feet, I have no need of you. Nay, much more those members of the body, which seem to be more feeble, are necessary: …

    1 Corinthians 13:1-7

    Though I speak with the tongues of men and of angels, and have not charity, I am become as sounding brass, or a tinkling cymbal. And though I have the gift of prophecy, and understand all mysteries, and all knowledge; and though I have all faith, so that I could remove mountains, and have not charity, I am nothing. And though I bestow all my goods to feed the poor, and though I give my body to be burned, and have not charity, it profiteth me nothing. …

    Philippians 2:4-8

    Look not every man on his own things, but every man also on the things of others. Let this mind be in you, which was also in Christ Jesus: Who, being in the form of God, thought it not robbery to be equal with God: …

Proof texts as given in the original; verse text from the King James Version.