Matthew 24:50
The lord of that servant shall come in a day when he looks not for him, and in an hour that he is not aware of,
Matthew 24:42-44
Watch therefore: for you know not what hour your Lord does come.
1 Thessalonians 5:2-3
For you yourselves know perfectly that the day of the Lord so comes as a thief in the night.
Revelation 3:3
Remember therefore how you have received and heard, and hold fast, and repent. If therefore you will not watch, I will come on you as a thief, and you will not know what hour I will come upon you.
Proverbs 29:1
He, that being often reproved hardens his neck, shall suddenly be destroyed, and that without remedy.