For by grace are ye saved through faith; and that not of yourselves: [it is] the gift of God: Not of works, lest any man should boast. (Ephesians 2:8-9)

And if by grace, then [is it] no more of works: otherwise grace is no more grace. But if [it be] of works, then is it no more grace: otherwise work is no more work. (Romans 11:6)

Now to him that worketh is the reward not reckoned of grace, but of debt. But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness. (Romans 4:4-5)