All saints being united to Jesus Christ their head, by his Spirit and by faith, have fellowship with him in his graces, sufferings, death, resurrection, and glory: and, being united to one another in love, they have communion in each other"rsquo;s gifts and graces, and are obliged to the performance of such duties, public and private, as to conduce to their mutual good, both in the inward and outward man. Saints by their profession are bound to maintain an holy fellowship and communion in the worship of God, and in performing such other spiritual services as tend to their mutual edification; as also in relieving each other in outward things, according to their several abilities and necessities. Which communion, as God offereth opportunity, is to be extended unto all those who, in every place, call upon the name of the Lord Jesus.
Westminster Confession of Faith
XXVIII The Communion of Saints