Matthew 24:48-51
But if that slave, with evil intent, should think to himself, 'My master will not be back very soon,'
Mark 13:32-37
But no one knows when that day or that hour will come; not even the angels in heaven or the Son of God know, but only the Father does.
Luke 21:34-36
"But pay attention to yourselves so that your hearts do not become overburdened by carousing, and drunkenness, and the worries of life. [If you do], that 'day' [i.e., Jesus' second coming and judgment] will arrive suddenly, like a trap [i.e., which catches an animal by surprise].
1 Thessalonians 5:2-3
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.
Revelation 3:3
So, remember how you have received and heard the message [i.e., they had eagerly accepted the Gospel]; [now] obey it and repent. For if you do not become [spiritually] alert, I will come as a thief [i.e. unexpectedly] and you will not know the [exact] time that I will come upon you [in judgment. See 2:16, 25].