2:25-29 No forms, ordinances, or notions can profit, without regenerating grace, which will always lead to seeking an interest in the righteousness of God by faith. For he is no more a Christian now, than he was really a Jew of old, who is only one outwardly: neither is that baptism, which is outward in the flesh: but he is the real Christian, who is inwardly a true believer, with an obedient faith. And the true baptism is that of the heart, by the washing of regeneration and the renewal of the Holy Ghost; bringing a spiritual frame of mind, and a willing following of truth in its holy ways. Let us pray that we may be made real Christians, not outwardly, but inwardly; in the heart and spirit, not in the letter; baptized, not with water only, but with the Holy Ghost; and let our praise be, not of men, but of God.
25-29. For circumcision—that is, One's being within the covenant of which circumcision was the outward sign and seal.
verily profiteth, if thou keep the law—if the inward reality correspond to the outward sign.
but if, &c.—that is, "Otherwise, thou art no better than the uncircumcised heathen."