50 the master of that servant will arrive on a day when he is not expecting him and at an hour of which he has not been informed;
Matthew 24:50 Cross References - WNT
Matthew 24:42-44
42 Be on the alert therefore, for you do not know the day on which your Lord is coming.
43 But of this be assured, that if the master of the house had known the hour at which the robber was coming, he would have kept awake, and not have allowed his house to be broken into.
44 Therefore you also must be ready; for it is at a time when you do not expect Him that the Son of Man will come.
1 Thessalonians 5:2-3
Revelation 3:3
3 Be mindful, therefore, of the lessons you have received and heard. Continually lay them to heart, and repent. If, however, you fail to rouse yourself and keep awake, I shall come upon you suddenly like a thief, and you will certainly not know the hour at which I shall come to judge you.