NET
6 And if it is by grace, it is no longer by works, otherwise grace would no longer be grace.
Darby
6 But if by grace, no longer of works: since [otherwise] grace is no more grace.
KJV
6 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.