Rabbi Yaron Reuven brings Chiddushim from Ohr HaChaim on Parashat Vayikra and animal sacrifices. Ohr HaChaim says, that according to the Scriptural exegesis to Leviticus 1:2, a heretic is forbidden from bringing a sacrifice for a sin. But there's another lesson from the verse that implies that there's an obligation for the righteous to do KIRUV to draw close those who have distanced themselves from HaShem and the Torah. Ohr HaChaim says that one who engages in KIRUV is so great they already gain atonement, and don't need to bring a sin offering!