Jamieson, Fausset & Brown

Even so have these--the Jews. now not believed--or, "now been disobedient" that through your mercy--the mercy shown to you. they also may obtain mercy--Here is an entirely new idea. The apostle has hitherto dwelt upon the unbelief of the Jews as making way for the faith of the Gentiles--the exclusion of the one occasioning the reception of the other; a truth yielding to generous, believing Gentiles but mingled satisfaction. Now, opening a more cheering prospect, he speaks of the mercy shown to the Gentiles as a means of Israel's recovery; which seems to mean that it will be by the instrumentality of believing Gentiles that Israel as a nation is at length to "look on Him whom they have pierced and mourn for Him," and so to "obtain mercy." (See Co2 3:15-16).