Avot281

1:
Our present mishnah continues the aggadic exposition which was started in the first mishnah. (The first few mishnayot of Chapter 5 follow the chronological order of the biblical narrative.)

2:
Our mishnah states that there were ten generations from Adam to Noah. The genealogy of Adam is given twice in the first few chapters of Genesis. We are given [Genesis 4:17-22] a list of the descendents of Adam's son Cain: Ĥanokh, Irad, Meĥuya'el, Metusha'el, Lemekh, Yaval and his siblings Yuval and Tuval-Cain – nine generations in all.

3:
However, at the very end of the chapter [Genesis 4:25-26] we are told that, after the murder of Abel by Cain, Adam and Eve had another son, Seth, and that Seth in turn had a son called Enosh. Chapter 5 then proceeds to offer a complete genealogy of Adam though his son Seth: Adam, Seth, Enosh, Kenan, Mehalel'el, Jered, Ĥanokh, Metushelaĥ, Lemekh, Noaĥ – ten generations in all.

4:
The sharp-eyed among us may notice that some of the names in both lists are either identical or tantalizingly similar. Those of a more traditional bent will doubtless assume that the Lemekh in the first list, the father of Yaval, Yuval and Tuval-Cain, was a different person from the Lemekh in the second list who was the father of Noaĥ: they just happened to have the same name. Similarly, Ĥanokh the father of long-lived Metushelaĥ had nothing to do with Cain's son, Ĥanokh. Those of a more critical bent will perhaps have different thoughts. However, this has nothing to do with our present discussion.

5:
Apparently, according to the thought process of the aggadah in our present mishnah, God realized almost immediately that the human race that He had created was a bad lot. So, why did it take Him so long to do something about it? The answer of our mishnah is that the delay of ten generations before the deliverance of the punishment serves to show how patient God is with evil-doers: He did not put an end to His unsuccessful experiment until the time of Noaĥ, by which time

And it was then that God destroyed everything that He had created by the great flood – ten generations after Adam's disobedience and the first murder.

6:
After the great flood God starts the experiment anew. Another ten generations pass. They too are detailed for us by the Torah [Genesis 11: 10-26]: Shem, Arfakhshad, Shelah, Ever, Peleg, Re'u, Serug, Naĥor, Teraĥ, Avraham – ten generations in all.

7:
The episode of the Tower of Babel [Genesis 11:1-9] shows God that this second experiment too has failed. Apparently, it will be impossible to bring the whole of mankind into a rapprochement with God (as was tried both in the Adamide experiment and in the Noahide experiment) and God now tries a new tactic: one man, Abraham, is chosen to be a shining example to the rest of mankind. Hopefully, he and his descendents will gradually bring the whole of mankind back into a rapprochement with God.

8:
In his commentary on our present mishnah Rabbi Ovadyah of Bertinoro notices an inconsistency: Adam's descendents were punished by the flood; Noah's descendents are not punished, but Abraham receives "the reward of them all". He writes:

9:
Apparently, the message of our mishnah is that while God has enormous patience with wrongdoing it is not infinite.