Romans 15:12 - Matthew Poole's English Annotations on the Holy Bible

And again, Esaias saith; viz. in Isaiah 11:10: see the notes there. This is a plain prophecy of the conversion of the Gentiles; their being received to mercy is implied in the former testimonies, but here it is expressed. The Son of David (the Savionr) shall rise and spring out of Jesse's root, and reign over the Gentiles by his word and Spirit. He shall gather them by the preaching of his cross, as by an ensign, and they, as it is in the prophet, shall seek to him; or, as it is here, shall trust or hope in him. The apostle, as he is wont, doth follow the LXX., which makes some little variation from the Hebrew text; but it is rather in sound than in sense. You have other prophecies and promises of the Gentiles mercy, as Isaiah 42:1,6 Isa 49:22 60:3,5; but the apostle thought, that these he had mentioned were sufficient for his purpose.