Leviticus 23:1,2

In this chapter Moses, by divine appointment, gives more particular directions about the observation of those solemnities which were before instituted. These, in our translation, are termed feasts; but the word מועדי, mognadee, here used, rather means solemn seasons, or meetings, and as the day of atonement was comprehended in them, which was not a feast, but a fast, they certainly are improperly termed feasts. The literal translation of the words is, solemnities of Jehovah, which ye shall proclaim for holy convocations, these are the solemnities. They are termed holy convocations, because on these days they were called together and assembled to hear the law, to offer sacrifices, and to address prayers and thanksgivings to God.