"The reason Our Lord was baptized was because it was part of the whole process of emptying, of humiliation, of the Incarnation. How could He be poor with us, if He did not in some way conform to our poverty? How could He come among sinful men to redeem them, if He did not also reveal the necessity of being purged from sin? There was no need of Our Blessed Mother to submit to the rite of purification, as there was no need of Our Lord to submit to the rite of Baptism by John. He had no need personally of having sins remitted, but He assumed a nature which was related to sinful humanity. Though He was without sin, He appeared to all men as a sinner, as He did on the cross. That was why He walked into the Jordan with all the rest of the sinners to demand the baptism of penance 'in remission of sins'." Venerable Archbishop Fulton Sheen.
This is from the archbishop's work These Are the Sacraments.
My theology professor requires us to read from the CCC so we understand the doctrines of the Church, so he can then explain the development of these doctrines. Today I read paragraphs 512-570. These paragraphs detail the mystery of the life of Our Lord, and the events of the Gospel which shed light on the mystery.
It dovetails very nicely with this Sheen quotation. The CCC adds this nice bit, from St. John the Baptist which we know from the Holy Mass. "Behold the Lamb of God, behold him who taketh away the sin of the world."
It also reminds me of what St. Athanasius said: God became man so that we might become gods.