Romans 15:9

"And that the Gentiles might glorify God for His mercy." But what he means is this. Those of the Jews would have had promises, even though they were unworthy. But thou hadst not this even, but wast saved from love towards man alone, even if, to put it at the lowest, they too would not have been the better for the promises, unless Christ had come. But yet that he might amalgamate (or temper) them and not allow them to rise up against the weak, he makes mention of the promises. But of these he says that it was by mercy alone that they were saved. Hence they are the most bound to glorify God. And a glory it is to God that they be blended together, be united, praise with one mind, bear the weaker, neglect not the member that is broken off. Then he adds testimonies, in which he shows that the man of the Jews ought to blend himself with those of the Gentiles; and so he says, "As it is written, For this cause I will confess to Thee among the Gentiles, O Lord, and will sing unto Thy Name."