Concerning the feasts of the Lord, which ye shall proclaim to be holy convocations, even these are my feasts. The translation should rather be, The appointed times which ye shall proclaim to be holy convocations, these are my appointed times.
The appointed times (mo'adin) include the great fast as well as the festivals, and the weekly and monthly as well as the annual holy days. The primary purpose with which the following enumeration of holy days is introduced, is to give a list of the holy convocations.
While the Israelites were still dwelling in the wilderness, a holy convocation appears to have been a religious assembly of all the males in the court of the tabernacle. After the settlement in Canaan, a religious gathering for prayer or festive rejoicing in all their dwellings, that is, wherever they lived, would have satisfied the command to hold a holy convocation, except on the three great festivals, when all who could, "kept the feast" at Jerusalem.
There were in all seven holy convocations in the year, besides the sabbath, namely, the first and last days of Unleavened Bread, the Feast of Pentecost, the Day of Atonement, the Feast of Trumpets, the first and last days of the Feast of Tabernacles.