Parashas Acharei Mos · Passuk 16:30
Chabad.org — English translation + Rashi
Torah Temima points to Yoma 85b.
English: R. Elazar b. Azaryah taught: “from all your sins before Hashem you shall be purified” — sins between man and God are atoned by Yom Kippur; sins between man and his fellow are not atoned until he appeases his fellow.
Scope of kapparah (bein adam laMakom vs. lachaveiro)
Yom Kippur’s atonement is limited to sins against God; interpersonal sins require prior reconciliation.