For in Christ Jesus - In his religion; see the note at Galatians 5:6.
But a new creature - The fact that a man is created anew, or born again, constitutes the real difference between him and other people. This is what Christ requires; this is the distinction which he designs to make. It is not by conformity to certain rites and customs that a man is to be accepted; it is not by elevated rank, or by wealth, or beauty, or blood; it is not by the color of the complexion; but the grand inquiry is, whether a man is born again, and is in fact a new creature in Christ Jesus; see the note at 2 Corinthians 5:17, for an explanation of the phrase “a new creature.”