Philo Judaeus De Decalogo 159

[159] And in speaking of the seventh here, I mean both that which is combined with the number six, the most generative of all numbers, and also that which, without being combined with the number six, is added to it, being made to resemble the unit, each of which numbers is reckoned among the festivals; for the lawgiver refers to the term, the sacred festival of the new moon, which the people give notice of with trumpets, and the day of fasting, on which abstinence from all meats and drinks is enjoined, which the Hebrews call, in their native language, pascha, on which the whole nation sacrifices, each individual among them, not waiting for the priests, since on this occasion the law has given, for one especial day in every year, a priesthood to the whole nation, so that each private individual slays his own victim on this day.