While nobody knows the day or the hour, we can read the signs that Jesus Himself gave us to be aware that His coming is near. Jesus Himself told us that.
It seems that the people of that time (when Jesus was around) would understand that phrase as an idiom pointing to one of the Seven Festivals of the Messiah (as I pointed out in another post, Post #202) -- The Feast of Trumpets. It was the one in which no one knew the day or hour of its coming... you see... :-)
The posts about the Feasts are so revealing and so helpful - and so awesome - thank you very very much!!!