Matthew 24:39
And the people [i.e., of Noah's day] did not know [when it would happen] until the Flood came and swept them all away. It will be the same way when the presence of the Son of man [arrives].
Matthew 24:50
that slave's master will return on a day that he least expects, and at an unknown hour.
Matthew 25:6
Then at midnight someone shouted, 'Look, the [bride and] groom are here. Come on, let us go out and meet them.'
1 Thessalonians 5:2
for you know perfectly well that the day of the Lord [i.e., when He returns, See II Thess. 2:1-2] will arrive like a thief coming in the night.
2 Peter 3:10
But the day of the Lord will come as a thief [i.e., unexpectedly]. At that time the heavens will pass away with a loud noise and the elements [Note: This refers either to the heavenly bodies or to the material components of the universe], will be dissolved with intense heat. And the earth and its works [i.e., its activities] will be burned up. [Note: Some translations render this phrase as it is in some ancient manuscripts, "will be disclosed," or "will be laid bare"].