Matthew 24:44

(Hom. in Ev. xiii. 5.) 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.

After this again, that they may not ask about it, He added, "Watch therefore, for ye know not what hour your Lord doth come." He said not, "I know not," but, "ye know not." For when He had brought them well nigh to the very hour, and had placed them there, again He deters them from the inquiry, from a desire that they should be striving always. Therefore He saith, "Watch," showing that for the sake of this, He did not tell it. "But know this, that if the good man 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." For this intent He tells them not, in order that they may watch, that they may be always ready; therefore He saith, When ye look not for it, then He will come, desiring that they should be anxiously waiting, and continually in virtuous action. But His meaning is like this: if the common sort of men knew when they were to die, they would surely strive earnestly at that hour. In order therefore that they may strive, not at that hour only, therefore He tells them not either the common hour, or the hour of each, desiring them to be ever looking for this, that they may be always striving. Wherefore He made the end of each man's life also uncertain. After this, He openly calls Himself Lord, having nowhere spoken so distinctly. But here He seems to me also to put to shame the careless, that not even as much care as they that expect a thief have taken for their money, not even this much do these take for their own soul. For they indeed, when they expect it, watch, and suffer none of the things in their house to be carried off; but ye, although knowing that He will come, and come assuredly, continue not watching, saith He, and ready so as not to be carried away hence unprepared. So that the day cometh unto destruction for them that sleep. For as that man, if he had known, would have escaped, so also ye, if ye be ready, escape free.