Ephesians 2:9

Not of works
Of any kind, moral or ceremonial, before or after conversion, done without faith or in it, nor of these in any sense; works are neither the moving causes, nor the procuring causes, nor the helping causes, nor "causa sine qua non", or conditions of salvation; the best works that are done by men, are not done of themselves, but by the grace of God, and therefore can never merit at his hand: and salvation is put upon such a foot,

lest any man should boast;
of his works before God, and unto men; wherefore he has denied works any place in justification and salvation, in order to exclude all boasting in man; and has fixed it in a way of grace, and has chosen and called poor sinful worthless creatures to enjoy it, that whoever glories, may glory in the Lord.