Easton's Bible Dictionary (1897)/Baptism of Christ
Baptism of Christ : Christ had to be formally inaugurated into the public discharge of his offices. For this purpose he came to John, who was the representative of the law and the prophets, that by him he might be introduced into his offices, and thus be publicly recognized as the Messiah of whose coming the prophecies and types had for many ages borne witness.
John refused at first to confer his baptism on Christ, for he understood not what he had to do with the "baptism of repentance." But Christ said, "`Suffer it to be so now,' NOW as suited to my state of humiliation, my state as a substitute in the room of sinners." His reception of baptism was not necessary on his own account. It was a voluntary act, the same as his act of becoming incarnate. Yet if the work he had engaged to accomplish was to be completed, then it became him to take on him the likeness of a sinner, and to fulfil all righteousness (Matt. 3:15).
The official duty of Christ and the sinless person of Christ are to be distinguished. It was in his official capacity that he submitted to baptism. In coming to John our Lord virtually said, "Though sinless, and without any personal taint, yet in my public or official capacity as the Sent of God, I stand in the room of many, and bring with me the sin of the world, for which I am the propitiation." Christ was not made under the law on his own account. It was as surety of his people, a position which he spontaneously assumed. The administration of the rite of baptism was also a symbol of the baptism of suffering before him in this official capacity (Luke 12:50). In thus presenting himself he in effect dedicated or consecrated himself to the work of fulfilling all righteousness.