Cyrill of Alexandria
The significance of consuming unleavened bread and refraining from work on the Sabbath, as well as the sanctity of the first and seventh days, has been clearly articulated in the earlier discussion (Ex. 12:15-16).
And the first day of them shall be venerable and holy: you shall not do any servile work therein.
בַּיּ֥וֹם הָרִאשׁ֖וֹן מִקְרָא־קֹ֑דֶשׁ כָּל־מְלֶ֥אכֶת עֲבֹדָ֖ה לֹ֥א תַעֲשֽׂוּ׃
One Church Father comments on this verse
The significance of consuming unleavened bread and refraining from work on the Sabbath, as well as the sanctity of the first and seventh days, has been clearly articulated in the earlier discussion (Ex. 12:15-16).
Passages read together with this verse.