You will say in that day: “I will give thanks to you, O LORD, for though you were angry with me, your anger turned away, and you did comfort me. Behold, God is my salvation; I will trust, and will not be afraid; for the LORD GOD is my strength and my song, and he has become my salvation. With joy you will draw water from the wells of salvation.” (Isaiah 12:1-3)
Elisha sent a messenger to him, saying, “Go and wash in the Jordan seven times, and your flesh shall be restored, and you shall be clean.” (2 Kings 5:10)
In the beginning, God the Father created the world through the Word of God. In Christ, the Word of God became part of creation. In Christ’s baptism the Word of God renews creation. Water is purified by Christ, and in turn becomes capable of washing away sin. Thus Christ, God incarnate, renews humanity from within by becoming flesh and uniting divinity to humanity, and from without by making water and creation capable of being the means for our salvation. The body, renewed from within by God, is washed with the waters of salvation. The inner renewal, and the external washing are both essential in salvation.
St. Irenaeus of Lyons (d. 202AD) writes:
“Man was created by God so that he might have life. If now, having lost life, wounded by the serpent, he could not return to life, but was to be fully abandoned to death, then God would be conquered and the malice of the serpent would have overcome His will. but since God is at once invisible and magnanimous, He has shown His magnanimity in correcting man and putting all men to the test, as we have said. Yet, by the second Adam, He has bound the strong man and destroyed his arms, and He has done away with death, bringing life to man who had been subject to death. For Adam had become the possession of the devil and the devil held him in his power, having perversely deceived him in subjecting him to death when he had offered him immortality. Indeed, in promising them that they would be like gods, which was not in his power, he brought about death in them. This is why he who made man captive was himself made captive by God, and man whom he had captured found himself freed from the slavery of condemnation.
The Logos of God was made flesh….to destroy death and to give life to man, for we were in the chains of sin and destined to be born through the state of sin and to fall under (the empire of) death.” (The Spirituality of the New Testament and Fathers by Louis Bouyer, pp 232-233)