John Gill Commentary Leviticus 23:4

"These are the set feasts of Jehovah, even holy convocations, which ye shall proclaim in their appointed season." — Leviticus 23:4 (ASV)

These are the feasts of the Lord, [even] holy convocations , &c.] What follow besides the sabbath mentioned: which you shall proclaim in their seasons ; the proper times of the year, the day or days, and month in which they are to be observed; these were to be proclaimed by the priests with the sound of trumpet, namely, what follow, for they are put together, which had been before for the most part singly delivered.