עֲשֵׂ֨ה זֹ֥את אֵפ֪וֹא ׀ בְּנִ֡י וְֽהִנָּצֵ֗ל כִּ֘י בָ֤אתָ בְכַף־רֵעֶ֑ךָ לֵ֥ךְ הִ֝תְרַפֵּ֗ס וּרְהַ֥ב רֵעֶֽיךָ׃
Uczyń to jedno, synu mój, abyś się ocalił - boś popadł w moc bliźniego twego - idź, rzuć się przed nim, i nalegaj usilnie na bliźniego twego.
Akeidat Yitzchak
The reason that sins committed between different human beings are not subject to atonement of Yom Kippur is, that any sin in which man's body is the major party, can only be atoned for by that same body making the appropriate restitution. When reconciling oneself with one's fellow man, it is the senior person, the scholar, who must make the first move, just as Abraham had done with his nephew Lot. (Genesis chapter 13)