'Generation' in the Bible

And he was very sad in spirit, and said, Why is this generation looking for a sign? truly, I say to you, No sign will be given to this generation.

Whoever has a feeling of shame because of me and my words in this false and evil generation, the Son of man will have a feeling of shame because of him, when he comes in the glory of his Father with the holy angels.

And he said to them in answer, O generation without faith, how long will I have to be with you? how long will I put up with you? let him come to me.

Truly, I say to you, This generation will not come to an end till all these things are complete.