Hebrews 11:8-10 referred to Abraham, Isaac and Jacob and showed that Abraham left the city of Ur of Chaldea and that he and Isaac and Jacob lived as nomads until Jacob transferred down to the land of Egypt in the days of his son Joseph. So during that period of time they did not live in a settled, established place like a city. Nothing in the Hebrew Scriptures says that God promised these three men a “city having real foundations, the builder and maker of which city is God.” That is Paul’s comment on the matter. Doubtless that expression refers to the established government of God by the ‘seed of Abraham,’ under which government those three patriarchs will live on earth and gain human perfection by the end of the thousand years.​—Gal. 3:16.

Hebrews 13:12-14 refers to Jesus’ being impaled outside the walls of earthly Jerusalem, or “outside the gate.” In the face of that circumstance Paul goes on to say, “Let us, then, go forth to him outside the camp [like the scapegoat or “the goat . . . for Azazel” that was sent into the wilderness on the day of atonement, (Lev. 16:10)], bearing the reproach he bore, for we do not have here a city that continues, but we are earnestly seeking the one to come.” This “city” refers to the heavenly kingdom, the New Jerusalem, which Paul mentions in Hebrews 12:22.

Spirit begettal of Christian men and women did not begin until Pentecost of 33 C.E. Those begotten of holy spirit from then on looked forward to life in the heavenly city prefigured by earthly Jerusalem.

That is why Paul in writing to Hebrew Christians could correctly say to them in Hebrews 12:22, “But you have approached a Mount Zion [not Mount Sinai in Arabia] and a city of the living God, heavenly Jerusalem, and myriads of angels.”

In line with all of this, Paul goes on to address himself to the spirit-begotten congregation in Hebrews 12:25-28, exhorting them to prove worthy of their heavenly kingdom, which is the “city of the living God, heavenly Jerusalem,” to which they have approached.