Commento su Esodo 12:15

שבעת ימים denotes a septaine (old French) of days.

שבעת ימים מצות תאכלו, "You shall eat unleavened bread for seven days, etc." This is connected to the fact that the Israelites' dough did not rise due to the suddenness of the redemption. You may well ask how the Torah could legislate (verse 14) a memorial for something that had not even taken place yet? After all, the dough did not rise because of the constant motion of the people carrying it on their backs, something that occurred on the morrow! They had not even slaughtered the Passover lamb yet and already the Torah speaks of an annual memorial to something that had not happened as yet! The whole Exodus would not occur until after the Israelites had slaughtered the Passover and eaten it with unleavended bread, and had thereby acquired the merit enabling G'd to take them out of Egypt! This is the day which G'd would remember for them in order to take them out, etc.

שבעת ימים מצות תאכלו, “you will eat unleavened bread for seven days.” The Torah commanded that unleavened bread be eaten for the seven days of the Matzot festival and that the first and last day be observed as “holy convocations,’ i.e. that on those days there is a work prohibition. The first day is holy as it commemorates the beginning of the redemption, the last day as it represents its conclusion. You are aware already that the seven days symbolise the six directions plus G’d all of whom partake in G’d’s and Israel’s joy. The involvement of G’d and His emanations in this joy is the reason we have been warned in Nechemyah concerning the need to rejoice on a festival viz.: “Go eat choice foods and drink sweet drinks and send portions to whoever has nothing prepared, for the day is holy to our Lord. Do not be sad for the rejoicing in the Lord is the source of your strength.”