How do Gentiles become fellow heirs and partakers of God's promise—by Judaism, the Mosaic law, or by Christ?
Gentiles become fellow heirs, of the same body, and partakers of God's promise in Christ, not by Judaism and not by the Mosaic law, but by Christ and His finished work. This was the mystery revealed to Paul, not made known in other generations, and once revealed it belongs to believers who must believe it.
Les explains that Ephesians 3:6 is one segment of the mystery Paul deals with. In other ages and past generations, this was not made known to the sons of men, but now it is revealed. The mystery is that Gentiles should be fellow heirs, of the same body, and partakers of His promise in Christ—not by Judaism, not by the Mosaic law, but by Christ and His finished work. Les points out that the Old Testament never spoke of Gentiles becoming one with Christ or with God, or one with the God of Abraham. Once this is revealed, it belongs to us, so we had better believe it.
That the Gentiles should be fellowheirs, and of the same body, and partakers of his promise in Christ by the gospel:
More Questions
Did the Old Testament ever say Gentiles would become one with the God of Abraham?
Nothing like this is found in the Old Testament: that Gentiles would become one with Christ or with God, that Gentiles would become one with the God of Abraham.