The day on which God showed Himself merciful to Moses and to His people, was the tenth day of Tishri, the day on which Moses was to receive the tables of the law from God for the second time, and all Israel spent it amid prayer and fasting, that the evil spirit might not again lead them astray. Their ardent tears and exhortations, joined with those of Moses, reached heaven, so that God took pity upon them and said to them: "My children, I swear by my lofty Name that these your tears shall be tears of rejoicing for you; that this day shall be a day of pardon, of forgiveness, and of the canceling of sins for you, for your children, and your children's children to the end of all generations."
How Israel Recovered After the Golden Calf Disaster
Legends of the Jews 2:125