Isaiah 49

Isaiah explains -

"And now, saith the Lord that formed me from the womb to be his servant, to bring Jacob again to him..."  (Isaiah 49:5)

Of such responsibility, the Lord -

"...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."  (Isaiah 49:6)

It is a requirement for exaltation.