A narrative-historical hermeneutic has to respect the distinctions and boundaries—even the cracks and disjunctions—that emerge in the telling of the story. If we allow ourselves to read later developments back into earlier passages, we muddy the waters and risk getting the whole story, to whatever degree, wrong. Scripture has to be read forwards, not backwards. So I have argued that the Gentile mission was a revelation of the risen Christ or of the Spirit to the post-Easter church. Prior to his death Jesus nowhere teaches that Gentiles will be included in the new covenant people. The impending intervention of YHWH in the history of his people will make an impact on the nations—indeed, news of this coming intervention will be proclaimed to the nations in the period leading up to the fall of Jerusalem and the temple. This is a familiar Old Testament idea: the Lord bears his holy arm before the eyes of the nations, and the ends of the earth will see God’s salvation of his people (Is. 52:9-10). It does not require some sort of ingathering of Gentiles into the family of Abraham.
Given that, let me try and explain what I think the so-called “great commission” to make disciples of all nations is all about (Matt. 28:19-20). We start with Jesus’ teaching on the Mount of Olives.