Who was God dealing with in the Old Testament and up to that point?
God was dealing with the nation of Israel, the Jews, from the Old Testament promises. His ministry and Word were confined to them, with only rare exceptions like the Roman Centurion and the woman of Canaan. The early scattered believers preached the Old Testament Word to none but Jews only.
Les explains that God had been dealing only with the Jew, with exceptions, and was dealing with the nation of Israel from the Old Testament promises. He points to Acts 11:19, where those scattered after Stephen's persecution traveled as far as Phoenix, Cyprus, and Antioch, preaching the Word. Les notes that Word was only the Old Testament, since no New Testament was written yet. They preached to none but Jews only. Les emphasizes this shows Gentiles were not in their listening audience, making it clear God's dealings were with Israel.