Matthew 24:36-40, 44

But of that day and hour knoweth no man, no, not the angels of heaven, but my Father only. But as the days of Noe were, so shall also the coming of the Son of man be. For as in the days that were before the flood they were eating and drinking, marrying and giving in marriage, until the day that Noe entered into the ark, and knew not until the flood came, and took them all away; so shall also the coming of the Son of man be. Then shall two be in the field; the one shall be taken, and the other left.

Therefore be ye also ready: for in such an hour as ye think not the Son of man cometh.