Leviticus 23:2

Speak with the sons of Israel, and say to them, The orders of the time of the Festivals of the Lord, which you shall proclaim as holy convocations, these are the orders of the time of My festivals.

After dealing with the sacrifices, Scripture proceeds to mention the days on which the children of Israel will offer burnt-offerings, beginning with the Sabbath. these are My chosen times Scripture employs the plural because there are many Sabbaths in a year [cf . :4].

SPEAK UNTO THE CHILDREN OF ISRAEL. The priests have no greater duties with regard to the festivals than the Israelites, therefore He did not admonish Aaron and his sons in this section, but the children of Israel, a term which includes all of them together, since He did not explain the Additional Offerings [for the festivals] in this section. However, He mentioned the festivals here in Torath Kohanim (i.e. Book of Leviticus) because they are days of offerings, and He alludes to them, just as He said, And ye shall bring an offering made by fire unto the Eternal, and at the end of this section He states, These are the appointed seasons of the Eternal, which ye shall proclaim to be holy convocations, to bring an offering made by fire unto the Eternal, a burnt-offering, and a meal-offering, a peace-offering, and drink-offerings., Verse 37. He did not, however, prolong the subject by explaining the Additional Offerings, since He did not want them to be binding upon the children of Israel when in the desert, and after He had counted [at the end of the desert period] those who were to come into the Land, as narrated in the Book of Numbers, and He commanded, Unto these the Land shall be divided, He then explained all the Additional Offerings in the section of Pinchas, which they were to offer in the Land immediately and throughout the generations. Therefore He said [here in this Book of Leviticus] with reference to [the Service on] the Day of Atonement, And he [i.e., Aaron] did as the Eternal commanded Moses, meaning that he did so in the desert [but the Additional Offerings for the other festivals were not binding in the desert].
Now He mentioned in this section the “he-lamb of the sheaf” and the two lambs of the Festival of Shevuoth,, Verse 19. because it is well-known that they were binding only in the Land, since they are brought on account of the bread [of the first-fruits], Verse 20. So also the he-lamb of the sheaf came on account of the meal-offering of the omer (Verse 12) which was binding only in the Land of Israel. concerning which He said, When ye are come into the Land which I give unto you, and shall reap the harvest thereof,, Verse 10. but the observance of the days themselves [as festivals] was binding immediately.
He mentioned the Sabbath among the appointed seasons which ye shall proclaim to be holy convocations, [although the Sabbath is not …

אשר תקראו אותם מקראי קודש, which you are to designate as periods of sanctified time. Whenever the word קרא appears in connection with the festivals it means the fixing of certain dates in the calendar. We have an example of this in Lamentation 1,15 where the prophet Jeremiah refers to the date on which the Temple was destroyed as קרא עלי מועד,”G’d having fixed the date the Jewish people was to experience this traumatic event including the killing of the flower of its youth.” Yonathan ben Uzziel, in translating Kohelet 2,15 כםקרה הכסיל, normally translated as “like the fate of the fool,” renders these words as מערע קדיש, [my version of the Targum renders the meaning of the verse quite differently, in a fatalistic sense, i.e. that G’d decrees death regardless of whether one is a fool or as wise as Solomon. Ed.]

מועדי ה' אשר תקראו אותם מקראי קודש, after the Torah had spoken on the subject of the animal offerings and the people offering them whose purpose it is to ensure that the Shechinah rests in/over the people of Israel. Compare Exodus 29,42 עולת תמיד לדורותיכם, פתח אהל מועד לפני ה' אשר אועד לכם שמה; “a regular burnt offering throughout the generations, at the entrance of the Tent of Meeting before the Lord.” The Torah spoke of the festivals, days on which one abstains from the pursuit of secular matters. On some of these days one has to abstain from such activities completely, on others only partially. For instance, on the Sabbath as well as on the Day of Atonement there is a total cessation of everything which is called מלאכה, work, in the sense of a productive activity. These days are meant for us to occupy ourselves exclusively with Torah and other sacred tasks. To this effect the Torah wrote (Exodus 20,9-10) “you shall labour for six days and conduct all your activities, whereas the seventh day is a Sabbath of the Lord your G’d.” On that day your activities should concern spiritual matters. On some of the days described as holy convocations there is a partial prohibition of work, desisting basically from the kind of activity related to the kind of labour involved in earning one’s livelihood. One is to enjoy these days. Concerning such days, our sages coined the phrase חציה לה' וחציה לכם, “half for G’d and half for you.” (Pessachim 68) There is no doubt that when the Jewish people conduct themselves in this fashion that the Divine Presence will be at home among them. Assaph expressed this thought in Psalms 82,1 which commences with the words אלוקים נצב בעדת א-ל וגו', “G’d stands in the divine assembly. Among the divine beings He pronounces judgment.” The meaning of the word מקראי קודש when applied to the days the Torah calls מועדי ה' אשר תקראו אותם מקראי קודש is: “days of assembles of the people for sacred undertakings.” The word מקרא refers to an assembly, just as the words שבת and חודש are understood as meaning assemblies both in Isaiah 1,13 and Isaiah 4,5