“Jesus sanctified baptism when he himself was baptized.
Who then is in a position to belittle baptism and still retain the faith after the moment in which the Son of God was baptized? He was immune from sin. So he did not submit to baptism to obtain the forgiveness of sins. Despite being free from sin, he submitted to baptism in order to bestow grace and dignity on those who would be baptized after him. He shared our flesh and blood in order that we might be partakers not only of his bodily existence but also of his divine grace.
And in the end he conquered death so that all of us might win salvation and be enabled to say: ‘O death, where is your victory? O death, where is your sting?’ [1 Cor. 15:55] In fact, the sting of death has been destroyed by means of baptism. When you go down into the water to be baptized, you take with you your sins. But the grace which is called down upon you marks your soul in a new way. You go down dead because of your sins: you come up given new life by grace. For if you were planted in the likeness of the Savior’s death, you were also thought worthy of resurrection.” (Drinking from the Hidden Fountain: A Patristic Breviary by Thomas Spidkik, pp 331-332)