Theophylact of Ohrid
Catena Aurea · Markusevangelium 13
But of that day and that hour knoweth no man, no, not the angels which are in heaven, neither the Son, but the Father. Take ye heed, watch and pray: for ye know not when the time is. For the Son of man is as a man taking a far journey, who left his house, and gave authority to his servants, and to every man his work, and commanded the porter to watch. Watch ye therefore: for ye know not when the master of the house cometh, at even, or at midnight, or at the cockcrowing, or in the morning: Lest coming suddenly he find you sleeping. And what I say unto you I say unto all, Watch.
See again that He has not said, I know not when the time will be, but, Ye know not. For the reason why He concealed it was that it was better for us; for if, now that we know not the end, we are careless, what should we do if we knew it? We should keep on our wickednesses even unto the end. Let us therefore attend to His words; for the end comes at even, when a man dies in old age; at midnight, when he dies in the midst of his youth; and at cockcrow, when our reason is perfect within us; for when a child begins to live according to his reason, then the cock cries loud within him, rousing him from the sleep ofsense; but the age of childhood is the morning. Now all these ages must look out for the end; for even a child must be watched, lest he die unbaptized.