The prophets of the Old Testament had focused their labours on the children of Abraham, to the near total exclusion of non-Jews. That the Spirit of Christ now preached the good news to the Gentiles of Asia Minor demonstrates the plan of God to give all people a place among those who can be born again and become heirs of the kingdom of heaven. Thus the Spirit can clarify precisely what he meant in prophecies as Genesis 12:3.
12 It was revealed to them that they were serving not themselves but you, in the things that have now been announced to you through those who preached the good news to you by the Holy Spirit sent from heaven, things into which angels long to look.