Blameless in his Generation Midrash on Genesis 6:9

(ט) אלה תולדת נח נח איש צדיק תמים היה בדרתיו את האלקים התהלךנח

(9) This is the line of Noah.—Noah was a righteous man; he was blameless in his generation; Noah walked with God.

(ב) בדרותיו יֵשׁ מֵרַבּוֹתֵינוּ דּוֹרְשִׁים אוֹתוֹ לְשֶׁבַח, כָּל שֶׁכֵּן אִלּוּ הָיָה בְדוֹר צַדִּיקִים הָיָה צַדִּיק יוֹתֵר; וְיֵשׁ שֶׁדּוֹרְשִׁים אוֹתוֹ לִגְנַאי, לְפִי דוֹרוֹ הָיָה צַדִּיק וְאִלּוּ הָיָה בְדוֹרוֹ שֶׁל אַבְרָהָם לֹא הָיָה נֶחְשָׁב לִכְלוּם (סנה’ ק”ח):

(2) בדורותיו IN HIS GENERATIONS — Some of our Rabbis explain this word to Noah's credit: he was righteous even in his generation; it follows that had he lived in a generation of righteous people he would have been even more righteous owing to the force of good example. Others, however, explain it to his discredit: in comparison with his own generation he was accounted righteous, but had he lived in the generation of Abraham he would have been accounted as of no importance (see Talmud, Sanhedrin 108a).

(בראשית ו, ט) אלה תולדות נח [נח איש צדיק תמים היה בדורותיו] א"ר יוחנן בדורותיו ולא בדורות אחרים וריש לקיש אמר בדורותיו כ"ש בדורות אחריםא"ר חנינא משל דרבי יוחנן למה הדבר דומה לחבית של יין שהיתה מונחת במרתף של חומץ במקומה ריחה נודף שלא במקומה אין ריחה נודף א"ר אושעיא משל דריש לקיש למה הדבר דומה לצלוחית של פלייטון שהיתה מונחת במקום הטנופת במקומה ריחה נודף וכ"ש במקום הבוסם

“This is the line of Noah; Noah was a righteous man, he was blameless in his generation” (Genesis 6:9)Rabbi Yoḥanan says: Relative to the other people of his generation he was righteous and wholehearted, but not relative to those of other generations. And Reish Lakish says: In his generation he was righteous and wholehearted despite being surrounded by bad influences; all the more so would he have been considered righteous and wholehearted in other generations.Rabbi Ḥanina says: There is a parable for the statement of Rabbi Yoḥanan; to what is this matter comparable? It is comparable to a barrel of wine that was placed in a cellar where vinegar is stored; in its place, its fragrance is noticeable, relative to the odor of the vinegar. When it is not in its place surrounded by vinegar, its fragrance is too subtle to be sensed.

Rabbi Oshaya says: There is a parable for the statement of Reish Lakish; to what is this matter comparable? It is comparable to a flask of perfume that was placed in a trash dump. Even there its fragrance is sweet, despite the ambient odor, and all the more so would it be noticeable in a clean place!

Kedushat Levi (1800-1860)

Why didn’t Noah pray to avert the decree? Because, there is a certain type of righteous person who serves the Creator, but is meek and worthless in his own eyes, and he thinks, from the depths of his heart: ‘Who am I to pray that a decree by averted?’ So, he doesn’t even pray to avert the decree. And Noah, even though he was righteous and whole-hearted (Gen 6:9), he was tiny and insignificant in his own eyes. He didn’t believe in himself, that he was a powerful holy person and he could actually avert the decree against the people. On the contrary, he saw himself just like everyone else in his generation, so he told himself: ‘I am no better than anyone else in my generation, so if I am going to be saved, so too will they.’ As a result, he did nothing to fight to save them.