Gregory the Great
Catena Aurea · Matthäusevangelium 24
Watch therefore: for ye know not what hour your Lord doth come. But know this, that if the goodman of the house had known in what watch the thief would come, he would have watched, and would not have suffered his house to be broken up. Therefore be ye also ready: for in such an hour as ye think not the Son of Man cometh.
(Hom. in Ev. xiii. 5.) Or, the thief breaks into the house through the neglect of the master of the house, when the spirit has slept upon its post of guard, and death has come in unawares into the dwelling house of our flesh, and finding the lord of the house sleeping, slays him; that is, the spirit, little providing for coming evils, is taken off unprepared, to punishment, by death. But if he had watched he would have been secure from the thief; that is, looking forward to the coming of the Judge, who takes our lives unawares, he would meet Him with penitence, and not perish impenitent. And the Lord would therefore have the last hour unknown, that it might always be in suspense, and that being unable to foresee it, we might never be unprepared for it.