Jesus took upon him the form of a servant (Philippians 2:7), the Servant of God, and this is an instance of his amazing humility. He - who is the Son of God, of the same nature with God, and equal to him - voluntarily became the Servant of him. He was chosen of God, in his eternal purposes, to be his Servant; and therefore is called, his Servant elect (Isaiah 42:1).
Accordingly, he was prophesied to be the Servant of the Lord (Zechariah 3:8; Isaiah 42:1). In the fullness of time he was sent and came not to be ministered to, as a monarch, but to minister as a servant under the law. His infancy in Egypt, where the Israelites were enslaved, was an emblem of that servile state he was come into, and very early he declared that he must be about his Father’s business.
As a servant, he had much work to do, and that very laborious. This was not only in working miracles, which were works his Father gave him to finish, as demonstrations of his Deity; nor only in going about from place to place to heal all manner of diseases, and so doing good to the bodies of men; nor only in preaching the gospel, for which he was qualified and sent, and thereby did good to the souls of men; but chiefly in fulfilling the law of God in the stead of his people.
But his greatest service was the redemption and salvation of men; for this was the work assigned to him by God his Father "to raise up the tribes of Jacob, and to restore the preserved of Israel." This was the work which was before him when be came, and this is the work he has finished, for he has obtained eternal redemption and has become the author of eternal salvation.
Now, throughout the whole of his work as a servant, he appeared very diligent and constant. Very early he discovered an eager inclination to be about it, and he was continually, constantly employed in it (John 4:34; 9:4). Nor did he stop working till he had completed the whole. In all which he was faithful to God who appointed him, which is why he justly obtained the character of God’s "righteous Servant" (Isaiah 11:5; 53:11).
Adapted from A Body of Doctrinal Divinity, Book 5, Chapter 3, by John Gill.