Ephesians 3:6

This is the content of the mystery (cf. Ephesians 2:11-22). First, Gentiles and Jews are fellow heirs of God’s riches that He presently bestows on believers (cf. Ephesians 2:19; Ephesians 1:13-14; Galatians 3:29; Galatians 4:7). Second, they are fellow members of the body of Christ, which is the church (Colossians 1:18). Third, they are fellow partakers of the promise concerning Christ in the gospel (i.e., that whoever trusts in Him has everlasting life; John 3:16; et al.). The mystery is not that Gentiles would enjoy salvation and enter into blessing along with Israel. God revealed that in the Old Testament (Genesis 12:3; Isaiah 42:6; et al.). It is that God has joined Jews and Gentiles as equals in one new body, which is the church (cf. 1 Corinthians 12:13). [Note: See Martin, p. 1308.]

"That Gentiles were to be saved was no mystery (Romans 9:24-33; Romans 10:19-21). The mystery ’hidden in God’ was the divine purpose to make of Jew and Gentile a wholly new thing-’the Church, which is his [Christ’s] body,’ formed by the baptism with the Holy Spirit (1 Corinthians 12:12-13) and in which the earthly distinction of Jew and Gentile disappears (Ephesians 2:14-15; Colossians 3:10-11). The revelation of this ’mystery’ of the Church was foretold but not explained by Christ (Matthew 16:18). The details concerning the doctrine, position, walk, and destiny of the Church were committed to Paul and his fellow ’apostles and prophets by the Spirit’ (Ephesians 3:5)." [Note: The New Scofield . . ., p. 1275.]