'Generation' in the Bible

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."

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."

He answered them, "You unbelieving generation! How much longer must I be with you? How much longer must I endure you? Bring him to me."

I tell you the truth, this generation will not pass away until all these things take place.