'Hour' in the Bible

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.

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;

"Keep awake therefore; for you know neither the day nor the hour.

Then He came to the disciples and found them asleep, and He said to Peter, "Alas, none of you could keep awake with me for even a single hour!