Israel was a people according to the flesh, separated in external things from all others, in a particular country which had been assigned to it as its abode.
The Church is a people drawn out of the midst of all others although dwelling in the midst of them, dispersed over the whole earth, and in which all national characteristics are completely set aside.
Israel's nationality was according to the flesh. Every one who was born of Israelitish parents, circumcision on the eighth day being observed, was an Israelite.
The Church's unity is according to the Spirit. It is neither pedigree according to the flesh, nor any ceremonial which makes a man to be a Christian, but only faith, and the being born of the Spirit.