But the descent into the water, and the trine immersion of the person in it, involves another mystery. For since the method of our salvation was made effectual not so much by His precepts in the way of teaching as by the deeds of Him Who has realized an actual fellowship with man, and has effected life as a living fact, so that by means of the flesh which He has assumed, and at the same time deified, everything kindred and related may be saved along with it, it was necessary that some means should be devised by which there might be, in the baptismal process, a kind of affinity and likeness between him who follows and Him Who leads the way.
Needful, therefore, is it to see what features are to be observed in the Author of our life, in order that the imitation on the part of those that follow may be regulated, as the Apostle says, after the pattern of the Captain of our salvation. For, as it is they who are actually drilled into measured and orderly movements in arms by skilled drill-masters, who are advanced to dexterity in handling their weapons by what they see with their eyes, whereas he who does not practise what is shown him remains devoid of such dexterity, in the same way it is imperative on all those who have an equally earnest desire for the Good as He has, to be followers by the path of an exact imitation of Him Who leads the way to salvation, and to carry into action what He has shown them.
It is, in fact, impossible for persons to reach the same goal unless they travel by the same ways. For as persons who are at a loss how to thread the turns of mazes, when they happen to fall in with some one who has experience of them, get to the end of those various misleading turnings in the chambers by following him behind, which they could not do, did they not follow him their leader step by step, so too, I pray you mark, the labyrinth of this our life cannot be threaded by the faculties of human nature unless a man pursues that same path as He did Who, though once in it, yet got beyond the difficulties which hemmed Him in.
I apply this figure of a labyrinth to that prison of death, which is without an egress and environs the wretched race of mankind. What, then, have we beheld in the case of the Captain of our salvation? A three days' state of death and then life again. Now some sort of resemblance in us to such things has to be planned. What, then, is the plan by which in us too a resemblance to that which took place in Him is completed? Everything that is affected by death has its proper and natural place, and that is the earth in which it is laid and hidden.
Now earth and water have much mutual affinity. Alone of the elements they have weight and gravitate downwards; they mutually abide in each other; they are mutually confined. Seeing, then, the death of the Author of our life subjected Him to burial in earth and was in accord with our common nature, the imitation which we enact of that death is expressed in the neighbouring element. And as He, that Man from above, having taken deadness on Himself, after His being deposited in the earth, returned back to life the third day, so every one who is knitted to Him by virtue of his bodily form, looking forward to the same successful issue, I mean this arriving at life by having, instead of earth, water poured on him, and so submitting to that element, has represented for him in the three movements the three-days-delayed grace of the resurrection.
Something like this has been said in what has gone before, namely, that by the Divine providence death has been introduced as a dispensation into the nature of man, so that, sin having flowed away at the dissolution of the union of soul and body, man, through the resurrection, might be refashioned, sound, passionless, stainless, and removed from any touch of evil. In the case however of the Author of our Salvation this dispensation of death reached its fulfilment, having entirely accomplished its special purpose.
For in His death, not only were things that once were one put asunder, but also things that had been disunited were again brought together; so that in this dissolution of things that had naturally grown together, I mean, the soul and body, our nature might be purified, and this return to union of these severed elements might secure freedom from the contamination of any foreign admixture. But as regards those who follow this Leader, their nature does not admit of an exact and entire imitation, but it receives now as much as it is capable of receiving, while it reserves the remainder for the time that comes after.
In what, then, does this imitation consist? It consists in the effecting the suppression of that admixture of sin, in the figure of mortification that is given by the water, not certainly a complete effacement, but a kind of break in the continuity of the evil, two things concurring to this removal of sin— the penitence of the transgressor and his imitation of the death. By these two things the man is in a measure freed from his congenital tendency to evil; by his penitence he advances to a hatred of and averseness from sin, and by his death he works out the suppression of the evil.
But had it been possible for him in his imitation to undergo a complete dying, the result would be not imitation but identity; and the evil of our nature would so entirely vanish that, as the Apostle says, “he would die unto sin once for all.” But since, as has been said, we only so far imitate the transcendent Power as the poverty of our nature is capable of, by having the water thrice poured on us and ascending again up from the water, we enact that saving burial and resurrection which took place on the third day, with this thought in our mind, that as we have power over the water both to be in it and arise out of it, so He too, Who has the universe at His sovereign disposal, immersed Himself in death, as we in the water, to return to His own blessedness.
If, therefore, one looks to that which is in reason, and judges of the results according to the power inherent in either party, one will discover no disproportion in these results, each in proportion to the measure of his natural power working out the effects that are within his reach. For, as it is in the power of man, if he is so disposed, to touch the water and yet be safe, with infinitely greater ease may death be handled by the Divine Power so as to be in it and yet not to be changed by it injuriously.
Observe, then, that it is necessary for us to rehearse beforehand in the water the grace of the resurrection, to the intent that we may understand that, as far as facility goes, it is the same thing for us to be baptized with water and to rise again from death. But as in matters that concern our life here, there are some which take precedence of others, as being those without which the result could not be achieved, although if the beginning be compared with the end, the beginning so contrasted will seem of no account (for what equality, for instance, is there between the man and that which is laid as a foundation for the constitution of his animal being?
And yet if that had never been, neither would this be which we see), in like manner that which happens in the great resurrection, essentially vaster though it be, has its beginnings and its causes here; it is not, in fact, possible that that should take place, unless this had gone before; I mean, that without the laver of regeneration it is impossible for the man to be in the resurrection; but in saying this I do not regard the mere remoulding and refashioning of our composite body; for towards this it is absolutely necessary that human nature should advance, being constrained thereto by its own laws according to the dispensation of Him Who has so ordained, whether it have received the grace of the laver, or whether it remains without that initiation: but I am thinking of the restoration to a blessed and divine condition, separated from all shame and sorrow.
For not everything that is granted in the resurrection a return to existence will return to the same kind of life. There is a wide interval between those who have been purified, and those who still need purification. For those in whose life-time here the purification by the laver has preceded, there is a restoration to a kindred state. Now, to the pure, freedom from passion is that kindred state, and that in this freedom from passion blessedness consists, admits of no dispute.
But as for those whose weaknesses have become inveterate, and to whom no purgation of their defilement has been applied, no mystic water, no invocation of the Divine power, no amendment by repentance, it is absolutely necessary that they should come to be in something proper to their case—just as the furnace is the proper thing for gold alloyed with dross—in order that, the vice which has been mixed up in them being melted away after long succeeding ages, their nature may be restored pure again to God. Since, then, there is a cleansing virtue in fire and water, they who by the mystic water have washed away the defilement of their sin have no further need of the other form of purification, while they who have not been admitted to that form of purgation must needs be purified by fire.
Source: The Great Catechism (New Advent)