Ephesians 2:9 - Matthew Poole's English Annotations on the Holy Bible

Not of works; any works whatever, and not only works of the ceremonial law: for if they only were excluded, the opposition between God and man, grace and works, were not right, which yet we find so often elsewhere; \see Romans 11:6\ men might not be saved by works of the ceremonial law, and yet still be saved by works, and of themselves. Lest any man should boast; glory in their own works or worth, as men are apt to do when they think they have any thing of their own which contributes to their salvation see Romans 3:27, Romans 4:2.