A גאון posted notices in shul on ראש חודש ניסן, listing the מראי מקומות for the דרשה that he was planning to give on שבת הגדול. Another רב, who was not nearly as sharp, would post such notices only on the day before his שבת הגדול דרשה. This was in accord with the statement in the פסח הגדה that יכול מראש חודש, if he is able to give a דרשה citing sources in ש״ס and פוסקים for which people need to prepare, then he should post the מראי מקומות on ראש חודש. But if his דרשה is תלמוד לומר ביום ההוא, like a תלמיד who plans on speaking דברי תורה פשוטים, then it’s sufficient if his notice is posted ביום ההוא.
05/07/2020