Charles Ellicott Commentary Romans 11:31

"even so have these also now been disobedient, that by the mercy shown to you they also may now obtain mercy." — Romans 11:31 (ASV)

Through your mercy—that is, through the mercy granted to you. The sight of the admission of the Gentiles is to act as a stimulus upon the Jews, and so lead to a renewal of their faith and obedience.