Isaiah 49:5 - Matthew Poole's English Annotations on the Holy Bible

To bring Jacob again to him; to convert the wicked and apostate Israelites unto God. Though Israel be not gathered; not brought home to God by my ministry. This word implies that the Israelites were divided and scattered from God, and divided among themselves, as they were in a high degree when Christ came into the world, and turned every one to his own way, as is said, Isaiah 53:6, and therefore needed to be gathered. Either it is a metaphor from wandering sheep, Which the good shepherd diligently seeketh, and bringeth home to the fold; or it is an allusion to the state of the Israelites, who either now were, or shortly were to be, dispersed into several parts of the world, from whence God had promised to gather them, and bring them into their own land, and unto his temple, Isaiah 43:5,6, and elsewhere. The sense is, Though Israel, God's own and only people, reject me, which will be an occasion of great wonder and scandal. Yet shall I be glorious in the eyes of the Lord; God will not despise me for the unsuccessfulness of my labours, but will honour and glorify me, both with himself and in the face of the world, in crowning my endeavours with glorious success among other people. My God shall be my strength, to support and strengthen me under this and all other discouragements and difficulties in the discharge of mine office.