Adam Clarke on Genesis 6:8

Noah found grace in the eyes of the Lord - Why? Because he was, 1. A just man, איש צדיק ish tsaddik, a man who gave to all their due; for this is the ideal meaning of the original word. 2. He was perfect in his generation - he was in all things a consistent character, never departing from the truth in principle or practice. 3. He walked with God - he was not only righteous in his conduct, but he was pious, and had continual communion with God. The same word is used here as before in the case of Enoch. See Gen 5:22.