Something often missed in scripture, simply because it is lost in translation, is that in the Greek there are three different words used in scripture that are rendered generation in the English, and the Author uses the three different words, to designate three different generations.
The primary sense of the word generation is what is generated by a generator, and in scripture it is the generator to which the Author is referring which determines which word the Author uses. When He uses genea, a word used for a natural son, to refer to someone, He is speaking of the naturally generated children of Israel generated by Jacob, as in This generation shall not pass, till all these things be fulfilledMatt 24:34 When the Author uses genos, a word used for adopted son, He is speaking of the church generated by adoption ye are a chosen generation, a royal priesthood1Pet 2:9 and, when He uses gennema He is speaking of all mankind generated by Adam: Ye serpents, ye generation of vipers, how can ye escape the damnation of hell?Matt 23:33
This becomes apparent when looking at scripture in which two of the different words translated generation are used together: You serpents, you generation [gennema: generated by Adam] of vipers, how can you escape the damnation of hell? Wherefore, behold, I send to you prophets, and wise men, and scribes: and some of them you shall kill and crucify; and some of them shall you scourge in your synagogues, and persecute them from city to city: That upon you may come all the righteous blood shed upon the earth, from the blood of righteous Abel to the blood of Zacharias son of Barachias, whom you slew between the temple and the altar. Verily I say to you, All these things shall come upon this generation [genea: generated by Jacob].Matt 23:33-36
Jesus is speaking of the atonement. How does mankind, generated by Adam, escape the damnation of hell? Mankind escapes the damnation of hell by all the sins of the world coming upon the one generated by Jacob, who bore those sins on the cross.