A.T. Robertson Commentary Romans 3:27

"Where then is the glorying? It is excluded. By what manner of law? of works? Nay: but by a law of faith." — Romans 3:27 (ASV)

It is excluded (εξεκλεισθη). First aorist (effective) passive indicative. "It is completely shut out." Glorying is on man's part.

Nay; but by a law of faith (ουχι, αλλα δια νομου πιστεως). Strong negative, and note "law of faith," by the principle of faith in harmony with God's love and grace.