Deuteronomy 16:8

On the seventh day shall be a solemn assembly. This is not placed in antithesis to the injunction, six days thou shalt eat unleavened bread, as if the Feast of Unleavened Bread ( mazzoth ) lasted only for six days and the seventh was to be devoted to a service of a different kind; it simply prescribes that the seventh day of the festival was to be celebrated by an assembling of the whole of those who had come to the feast; the festival was to be wound up with a day of holy convocation, in which no work was to be done ( Leviticus 23:36 ). On all the days unleavened bread was to be eaten, and on the seventh there was besides to be a solemn assembly to the Lord ( עֲצֶרֶת ), called in Le 23:36, "a holy convocation" ( מִקְרָא קֹדֶשׁ ).