Ravin bar Rav Adda said in the name of Rabbi Yitzchak: Whoever is used to coming to the beis knesses and did not come one day, HaKadosh Baruch Hu asks about him, as it says, “Who among you fears Hashem and listens to the voice of His servant, who walks in darkness with no light?” (Yeshayahu 50:10). If he went for a mitzvah, he has light; and if he went for an optional matter, he has no light. “Let him trust in the Name of Hashem” (Yeshayahu 50:10): what is the reason? Because he should have trusted in the Name of Hashem, and did not trust.2