John 5:4

What was done, then, that they who could not be healed in the porches might be healed in that water after being troubled? For on a sudden the water was seen troubled, and that by which it was troubled was not seen. Thou mayest believe that this was wont to be done by angelic virtue, yet not without some mystery being implied. After the water was troubled, the one who was able cast himself in, and he alone was healed: whoever went in after that one, did so in vain. What, then, is meant by this, unless it be that there came one, even Christ, to the Jewish people; and by doing great things, by teaching profitable things, troubled sinners, troubled the water by His presence, and roused it towards His own death? But He was hidden that troubled. For had they known Him, they would never have crucified the Lord of glory. Wherefore, to go down into the troubled water means to believe in the Lord's death. There only one was healed, signifying unity: whoever came thereafter was not healed, because whoever shall be outside unity cannot be healed.

(Tr. xvii. c. 3) So then Christ came to the Jewish people, and by means of mighty works, and profitable lessons, troubled the sinners, i. e. the water, and the stirring continued till He brought on His own passion. But He troubled the water, unknown to the world. For had they known Him, they would not have crucified the Lord of glory. (1 Cor. 11) But the troubling of the water came on all at once, and it was not seen who troubled it. Again, to go down into the troubled water, is to believe humbly on our Lord's passion. Only one was healed, to signify the unity of the Church: whoever came afterwards was not healed, to signify that whoever is out of this unity cannot be healed. Wo to them who hate unity, and raise sects.

What manner of cure is this? What mystery doth it signify to us? For these things are not written carelessly, or without a purpose, but as by a figure and type they show in outline things to come, in order that what was exceedingly strange might not by coming unexpectedly harm among the many the power of faith. What then is it that they show in outline? A Baptism was about to be given, possessing much power, and the greatest of gifts, a Baptism purging all sins, and making men alive instead of dead. These things then are foreshown as in a picture by the pool, and by many other circumstances. And first is given a water which purges the stains of our bodies, and those defilements which are not, but seem to be, as those from touching the dead, those from leprosy, and other similar causes; under the old covenant one may see many things done by water on this account.

First then, as I before said, He causeth defilements of our bodies, and afterwards infirmities of different kinds, to be done away by water. Because God, desiring to bring us nearer to faith in baptism, no longer healeth defilements only, but diseases also. For those figures which came nearer in time to the reality, both as regarded Baptism, and the Passion, and the rest, were plainer than the more ancient; and as the guards near the person of the prince are more splendid than those before, so was it with the types. And "an Angel came down and troubled the water," and endued it with a healing power, that the Jews might learn that much more could the Lord of Angels heal the diseases of the soul. Yet as here it was not simply the nature of the water that healed, (for then this would have always taken place,) but water joined to the operation of the Angel; so in our case, it is not merely the water that worketh, but when it hath received the grace of the Spirit, then it putteth away all our sins. Around this pool "lay a great multitude of impotent folk, of blind, halt, withered, waiting for the moving of the water"; but then infirmity was a hindrance to him who desired to be healed, now each hath power to approach, for now it is not an Angel that troubleth, it is the Lord of Angels who worketh all. The sick man cannot now say, "I have no man"; he cannot say, "While I am coming another steppeth down before me"; though the whole world should come, the grace is not spent, the power is not exhausted, but remaineth equally great as it was before. Just as the sun's beams give light every day, yet are not exhausted, nor is their light made less by giving so abundant a supply; so, and much more, the power of the Spirit is in no way lessened by the numbers of those who enjoy it. And this miracle was done in order that men, learning that it is possible by water to heal the diseases of the body, and being exercised in this for a long time, might more easily believe that it can also heal the diseases of the soul.