1 Clement 7:6
First Epistle of Clement to the Corinthians5 Let us look back at all the generations in turn and learn how, from age to age, the Master has given a place for repentance to those who desire to turn to Him. 6 Noah preached repentance, and those who obeyed were saved. 7 Jonah preached destruction to the people of Nineveh, but they repented of their sins, obtained pardon from God through their supplications, and received salvation, even though they were strangers to Him.
Sanhedrin 108a
Babylonian TalmudRabbi Yosei from Caesarea taught: What is the meaning of that which is written: “He is swift upon the face of the waters; their portion is cursed in the earth; he turns not by way of the vineyards” (Job 24:18)? This teaches that Noah the righteous would rebuke the people of his generation and say to them: Repent. And if you do not, the Holy One, Blessed be He, will bring a flood upon you and float your corpses on the water like wineskins filled with air that float on water, as it is stated: “He is swift upon the face of the waters.” Moreover, a curse is taken from them to all who enter the world, as people will curse others, saying: They shall be like the generation of the flood. As it is stated: “Their portion is cursed in the earth.”
Notes and References
"... As for Noah's (unspoken) good deeds before the flood, they came to be connected to this idea of a warning prior to the flood. For if Noah had 'found favor in the eyes of the Lord,' was it not merely logical that he himself - by his example, or perhaps by actual exhortation - had tried to turn his fellow human beings away from sin and so save them from destruction? Support for this idea was found, once again, in the passage cited above: Then the Lord said, 'My spirit shall not abide in man for ever, for he is flesh, but his days shall be a hundred and twenty years.' - Genesis 6:3. Said to whom? If the reference to one hundred and twenty years was indeed a warning, then this warning must have been spoken to some human being(s) in the hope of being heeded. Since Noah is later singled out as the righteous man of his time, it seemed only natural to interpreters that the divine warning was spoken to him - and that he must have immediately passed it along to his contemporaries, perhaps trying to get them to mend their ways and so be saved. Thus emerged the figure of Noah the preacher ..."
Kugel, James L. The Bible as it Was (pp. 114-115) Harvard University Press, 1998