Mark 13:30-37

30 Verily I say to you, that this generation may not pass away till all these things may come to pass;

31 the heaven and the earth shall pass away, but my words shall not pass away.

32 `And concerning that day and the hour no one hath known -- not even the messengers who are in the heaven, not even the Son -- except the Father.

33 Take heed, watch and pray, for ye have not known when the time is;

34 as a man who is gone abroad, having left his house, and given to his servants the authority, and to each one his work, did command also the porter that he may watch;

35 watch ye, therefore, for ye have not known when the lord of the house doth come, at even, or at midnight, or at cock-crowing, or at the morning;

36 lest, having come suddenly, he may find you sleeping;

37 and what I say to you, I say to all, Watch.'