Listen, O isles, unto me; and hearken, ye people, from far; The Lord hath called me from the womb; from the bowels of my mother hath he made mention of my name.
And he hath made my mouth like a sharp sword; in the shadow of his hand hath he hid me, and made me a polished shaft; in his quiver hath he hid me;
And said unto me, Thou art my servant, O Israel, in whom I will be glorified.
Then I said, I have laboured in vain, I have spent my strength for nought, and in vain: yet surely my judgment is with the Lord, and my work with my God.
And now, saith the Lord that formed me from the womb to be his servant, to bring Jacob again to him, Though Israel be not gathered, yet shall I be glorious in the eyes of the Lord, and my God shall be my strength.
And he said, It is a light thing that thou shouldest be my servant to raise up the tribes of Jacob, and to restore the preserved of Israel: I will also give thee for a light to the Gentiles, that thou mayest be my salvation unto the end of the earth.
God ultimately called Jesus to glorify Him. He was supposed to restore Israel but that nation despised and rejected Him. The Lord then used Jesus to go out to the Gentiles and bring them into the fold. They who were considered dogs are now blessed to receive the salvation that Israel abandoned.
Paul alludes to this verse in reference to Barnabas and himself in Acts 13:47. He saw himself as sharing in the work of the Jesus as he brought the light of the gospel to the gentiles. I believe that we too can also share in that same work. Jesus did say that we are the salt and light of the world.
Then said Jesus to them again, Peace be unto you: as my Father hath sent me, even so send I you.