On Yom Kippur, God atones for the sins of His children and purifies them. Nevertheless, the Sages explain that there are certain caveats: Someone who has hurt another can achieve atonement only if he first placates his victim. Furthermore, the sins of one who relies in advance on the atonement that will come on Yom Kippur will not be atoned.

Concerning one who says: I will sin and I will then repent, I will sin and I will then repent, he will not be provided with the opportunity to repent. Concerning one who says: I will sin and Yom Kippur will atone, Yom Kippur will not atone.

For transgressions between a person and the Omnipresent, Yom Kippur atones; for transgressions between one person and another, Yom Kippur does not atone until he appeases the other. Rabbi Elazar ben Azarya expounded: “From all your sins before the Lord you shall be purified” (Leviticus 16:30). For transgressions between a person and the Omnipresent, Yom Kippur atones, but for transgressions between one person and another, Yom Kippur does not atone until he appeases the other. (Mishna Yoma 8:9)