Matthew 12:39-40

12:39 But he answered them, “An evil and adulterous generation asks for a sign, but no sign will be given to it except the sign of the prophet Jonah. 12:40 For just as Jonah was in the belly of the huge fish for three days and three nights, so the Son of Man will be in the heart of the earth for three days and three nights.

Mark 8:12

8:12 Sighing deeply in his spirit he said, “Why does this generation look for a sign? I tell you the truth, no sign will be given to this generation.”

Mark 8:38

8:38 For if anyone is ashamed of me and my words in this adulterous and sinful generation, the Son of Man will also be ashamed of him when he comes in the glory of his Father with the holy angels.”

Acts 2:40

2:40 With many other words he testified and exhorted them saying, “Save yourselves from this perverse generation!”