"These are the generations of Noah." Rest for the heavens and rest for humanity. Every place that it says, "these are" it adds something to the earlier subject, when it says "these", it cuts off the earlier subject. And here it cuts off the generation of the flood, that they were wicked ones and Noah and his sons were more righteous than them.
Wherever אלה, “these are”, is used it cuts off (פוסל) the preceding section from that which it introduces; where, however, ואלה “and these” is used it adds something to the former subject (i. e. forms a continuation of it). So also here: “And these are the judgments (i. e. these, also)”: "A righteous man." Because he did righteous acts with creatures, that he fed them all the time they were upon the ark, that is why he is called a righteous person "Perfect."
That he was born circumcised, as it is stated, "Noah walked with God" (Genesis 6:9) because he was perfect. "In his generation." And not in the generations of the righteous ones. And there are those who say that with the wicked, he was a righteous person who did not learn from their deeds, and if he would have been in the generation of the righteous ones, how much more so would he have been a righteous person!
"With God." Noah walked in the ways of his ancestors, as it is stated, "The God in whose ways my fathers walked." (Genesis 48:15) That they did not need help to be righteous ones, but Noah, "Noah walked with God", that if the Holy One had not held him, Noah would not have been able to stand.