YOM KIPPUR: FORGIVEN FOR THE SIN OF THE GOLDEN CALF

Moshe descended from Mount Sinai the third time on the tenth of Tishrei which would become Yom Kippur. Therefore, this day was established as a decree and remembrance for all generations. In Leviticus / Vayikra 16:34 it is written:

Leviticus 16:34 And this shall be an everlasting statute unto you, to make an atonement for the children of Israel for all their sins once a year. And he did as the Lord commanded Moses.