Question:

What is the correct (i.e. orthodox) position on the "communion of saints" affirmed in the Apostle's Creed?

Answer:

I do not think I can do any better to answer your question about the Communion of the Saints than the authors of our Confession of Faith, so I will quote it and provide you the Scripture support:

CHAPTER XXVI

Of the Communion of Saints

I. All saints, that are 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's gifts and graces, and are obliged to the performance of such duties, public and private, as do conduce to their mutual good, both in the inward and outward man.

Romans 1:11-14; 6:5, 6; 8:17; 1 Corinthians 3:21-23; 12:7, 12; Galatians 6:10; Ephesians 2:5, 6; 3:16-18; 4:15, 16; Philippians 3:10; Colossians 2:19; 1 Thessalonians 5:11; 2 Timothy 2:12; 1 John 1:3; 3:16-18.

II. Saints by profession are bound to maintain a 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.

Isaiah 2:3; Acts 2:42-46; 11:29, 30; 1 Corinthians 11:20; 2 Corinthians 8-9; Hebrews 10:24, 25; 1 John 3:17

III. This communion which the saints have with Christ, doth not make them in any wise partakers of the substance of his Godhead; or to be equal with Christ in any respect, either of which to affirm is impious and blasphemous. Nor doth their communion one with another, as saints, take away, or infringe the title or propriety which each man hath in his goods and possessions.

Psalm 45:6, 7; John 1:14; 20:17; 1 Corinthians 8:6; Colossians 1:18, 19; Hebrews 1:6-9; Exodus 20:15; Acts 5:4; Ephesians 4:28

It is important to know that in the New Testament the word translated in our English Bibles as "saints" (from the Latin) means "holy people". This is not a designation of some Christians within the larger church but is the identity of all who belong to Jesus Christ (see 1 Cor. 1:2). I am a "saint", not because I have attained to a higher level of holiness than other Christians, but because in Jesus Christ (the Holy One) I have been declared holy as God's gift of grace in spite of my many sins (see Romans 3:19-24; Philippians 3:3-9), received by faith in Christ.

In its most basic sense, when referring to humans and other things, "holiness" indicates separation from the common to be devoted to the honor and service of God. The garments of the Old Testament priests were holy because they were worn by the priests in their service of God in the tabernacle and temple. The same is true of the holy plates and bowls and candlesticks. They were for God's use only and not for common use. And so those who belong to God by the redeeming work of Christ are His holy people, called out of the world and into His holy church.

The word "communion" means "sharing". For example, in the Lord's Supper, Christian believers share together the loaf and the cup, symbolic of sharing together in the body and blood of Christ, that is, in His atoning work on the cross.