What is heart circumcision in the Spirit?
Physical circumcision cuts off what is superfluous in the flesh; at salvation, the old Adam is cut off, producing an inward circumcision of the heart in the Spirit. This is not in the letter or outward Law-keeping; its praise is not of men but of God.
Les explains that circumcision cuts off that which is superfluous in the flesh. The spiritual question is what is superfluous in the Spirit, and the answer is the old Adam. So at salvation, our old Adam is cut off, and it becomes a heart circumcision. It is that of the heart in the Spirit, and not in the letter, keeping the Law, whose praise is not of men, but of God. After this, the text moves into chapter 3, the final condemnation, where Paul asks what advantage the Jew had or what profit circumcision had, and answers much every way, because they had the covenant promises, the Old Testament, the prophets, the Psalms, the temple, the priesthood, and chiefly the oracles of God.