Charles Ellicott Commentary Romans 11:6

"But if it is by grace, it is no more of works: otherwise grace is no more grace." — Romans 11:6 (ASV)

And if by grace.—The true text of this verse differs considerably from that which is translated in the Authorized Version, “But if by grace, then is it no more of works, otherwise grace is no more seen to be grace.”

The preservation of the remnant cannot be due to grace and works at the same time; it must be due to one or the other.