Matthew 12:38–41 (ESV)
38 Then some of the scribes and Pharisees answered him, saying, “Teacher, we wish to see a sign from you.”
39 But he answered them, “An evil and adulterous generation seeks for a sign, but no sign will be given to it except the sign of the prophet Jonah.
40 For just as Jonah was three days and three nights in the belly of the great fish, so will the Son of Man be three days and three nights in the heart of the earth.
41 The men of Nineveh will rise up at the judgment with this generation and condemn it, for they repented at the preaching of Jonah, and behold, something greater than Jonah is here.
Matthew 24:42 (ESV)
42 Therefore, stay awake, for you do not know on what day your Lord is coming.
Luke 21:25 (ESV)
25 “And there will be signs in sun and moon and stars, and on the earth distress of nations in perplexity because of the roaring of the sea and the waves,
Luke 21:36 (ESV)
36 But stay awake at all times, praying that you may have strength to escape all these things that are going to take place, and to stand before the Son of Man.”
Luke 12:56 (ESV)
56 You hypocrites! You know how to interpret the appearance of earth and sky, but why do you not know how to interpret the present time?
Matthew 25:13 (ESV)
13 Watch therefore, for you know neither the day nor the hour.
1 Thessalonians 5:4 (ESV)
4 But you are not in darkness, brothers, for that day to surprise you like a thief.
Hebrews 10:23–25 (ESV)
23 Let us hold fast the confession of our hope without wavering, for he who promised is faithful. 24 And let us consider how to stir up one another to love and good works, 25 not neglecting to meet together, as is the habit of some, but encouraging one another, and all the more as you see the Day drawing near.