What did saint Paul mean when he says that the church is like a temple of living stones and Jesus is the keystone?

Answer 1

Paul did indeed refer to the church (metaphorically) as a "building" (see Ephesians 2:19-22), but it was Peter who described the church as being made up of "living stones." He first refers to Christ as a "living stone," then extends the analogy to all Christians.

1 Peter 2:4, 5 - Coming to Him as to a living stone, rejected indeed by men, but chosen by God and precious, you also, as living stones, are being built up a spiritual house, a holy priesthood, to offer up spiritual sacrifices acceptable to God through Jesus Christ.

Peter then reminds his readers that the prophets spoke of Jesus as a "chief cornerstone" (not "keystone") in verse six, where he quotes Isaiah 28:16.

Therefore it is also contained in the Scripture, "Behold, I lay in Zion A chief cornerstone, elect, precious, And he who believes on Him will by no means be put to shame."

The New Testament teaching is clear that Jesus' church is not a literal building, nor is it an "organization." It is a body of true believers, united not by tenet or man-made doctrine, but by faithful obedience to the gospel of Christ, who "are being built together for a dwelling place of God in the Spirit." (Ephesians 2:22). As opposed to a temporal house made of literal stones, the church is a spiritual house made of "living stones."