Do you have to separate God's dealing with the Old Testament economy from His dealing with the Church?
Yes. God's dealings with the Old Testament economy and His dealings with the Church must be kept separate and cannot be mixed. Israel and the Church are two separate economies; the phrase 'in Christ' is uniquely Pauline and describes the Body of Christ, not Israel under law.
Les teaches that in all his years of teaching, if one thing has come through, it is that God's dealing with the Old Testament economy and His dealing with the Church must be separated. You cannot mix them; you have to keep them sorted. He explains that to understand verse 23, you must realize Israel and the Church are two separate economies. An economy is a system that makes something go, like the economy of a nation comprising business, politics, and more. He also notes that the positional term 'in Christ' is uniquely the Body of Christ; the Jew in the economy of law is never spoken of as being in Christ, which is strictly a Pauline term.