Midrasch zu Jechezkiel 18:15

R. Yehudah says: It is written (Psalms 18:1-5) "Who will sojourn in Your tent? —- one who walks in innocence and works righteousness … who has no slander on his tongue … who despises the shameful one … who does not lend his money on interest." And elsewhere it is written (Ezekiel 18:15) "And if a man would be a tzaddik — he did not eat of (the idolatries of) the mountains, and he did not lift his eyes to the idols of the house of Israel, and he did not defile his neighbor's wife, and he did not come near a niddah, etc. … (Ibid. 9) he is a tzaddik; he will live!" Now what did this man do, (aside from what he did not do)? We are hereby apprised that if one sits (passively) and does not transgress, he is given the reward of the doer of a mitzvah.