“The foundations of the prison-house,” we read, “were shaken” where Paul was bound, “and every one's bands were loosed.” Beholdest thou then in bonds a nature that can dissolve bonds themselves? For as the Lord's death put death itself to death, so also did Paul's bonds loose the men in bonds, shake the house of bondage, open the doors. Yet is not this the natural effect of bonds, but the very reverse; it is to keep him that is bound in safety, not to open for him the prison walls. No, of bonds then in general this is not the nature, but of those bonds which are for Christ's sake, it is. “The jailor fell down before Paul and Silas.” And yet neither is this again the effect of chains in general, to lay the binders at the feet of the bound: no, but, on the contrary, to put these last under the hands of the former. Whereas here, the man who was free was under the feet of the man who had been bound. The binder was beseeching him whom he had bound to release him from his fear. Tell me, was it not thou that bound him? Did you not cast him into the inner prison? Did you not make his feet fast in the stocks? Why do you tremble? Why are you troubled? Why do you weep? Why have you drawn your sword? Never bound I, says he, anything like this! I knew not that the prisoners of Christ had power so mighty as this. What do you say? They received power to open Heaven, and should they not be able to open a prison? They loosed them that were bound by evil spirits, and was a piece of iron likely to conquer them? You know not the men. And therefore also were thou pardoned. That prisoner is Paul, whom all the Angels reverence. He is Paul, whose very handkerchiefs and napkins cast out devils, and chase diseases to flight. And sure the bond which is of the devil is adamantine, and far more indissoluble than iron; for this indeed binds the soul, the other only the body. He therefore that released souls that were bound, shall not he have power to release his own body? He that could burst asunder the bonds of evil spirits, shall he not unloose a rivet of iron? He that by his very garments unloosed those prisoners, and released them from the spell of devils, shall not he of himself set himself at liberty? For this was he first bound himself, and then loosed the prisoners, that you might understand that Christ's servants in bonds possess a power far greater than they that are at liberty. Had one who was at liberty wrought this, then had it not been so marvellous. So then the chain was not a token of weakness, but rather of a greater power, and thus is the saint's might more illustriously displayed, when, even though in bonds, he overpowers them that are at liberty, when he that is in bonds sets not only himself at liberty, but them that are in bonds also. Where is the use of walls? What the advantage of thrusting him into the inner prison, whereas he opened the outer also? And why too was it done in the night? And why with an earthquake?
Oh, bear with me a little, and give me leave while I refrain from the Apostle's words, and revel in the Apostle's deeds, and banquet on Paul's chain; grant me still longer to dwell upon it. I have laid hold on that chain, and no one shall part me from it. More securely at this moment am I bound by affection, than was he then in the stocks. This is a bond which no one can loose, for it is formed of the love of Christ; this neither the Angels, no, nor the kingdom of Heaven, has power to unloose. We may hear Paul's own words; “Neither angels, nor principalities, nor things present, nor things to come, nor powers, nor height, nor depth, shall be able to separate us from the love of God which is in Christ Jesus our Lord.”
Now then, why did the event take place at midnight? And wherefore too with an earthquake? Hearken, and marvel at the providential orderings of God. Every one's bands were loosed, and the doors were opened. And yet was this done only for the jailor's sake, not with a view to display, but with a view to his salvation: for that the prisoners knew not that they were loosed, is evident from Paul's exclamation; for what said he? “He cried with a loud voice, saying, Do yourself no harm, for we are all here.” But never would they all have been within, had they seen the doors opened, and themselves set at liberty. They who were used to cut through walls, and to scale roofs and parapets, and to venture on all sorts of attempts in chains, never would have endured to remain within, with their bands loosed, and the doors opened, with the jailer himself asleep; no, but the bond of sleep was to them instead of the bonds of iron. So that the thing took place and yet no damage ensued from the miracle to the jailer who was to be saved. And besides this too, they that are bound are bound most securely in the night, not in the day; and so accordingly might we behold them bound again with all care and sleeping: but had these things been done in the day time, there would have been great stir and tumult.
Source: Homilies on Ephesians (New Advent)