Q - If Rosh-hodesh (day of the new moon) falls on the Sabbath, and one forgot, while saying grace after his evening or morning meal, to mention the holiday, what must he do? A - If he had commenced the recitation of the fourth benediction, then he must again say grace from the beginning. This applies only to Rosh-hodesh that falls on the Sabbath, and not in the case where Rosh-hodesh falls on a week-day, for only in the former instance is one actually required to partake of a meal.