Albert Barnes Commentary Leviticus 23:5-8

"In the first month, on the fourteenth day of the month at even, is Jehovah`s passover. And on the fifteenth day of the same month is the feast of unleavened bread unto Jehovah: seven days ye shall eat unleavened bread. In the first day ye shall have a holy convocation: ye shall do no servile work. But ye shall offer an offering made by fire unto Jehovah seven days: in the seventh day is a holy convocation; ye shall do no servile work." — Leviticus 23:5-8 (ASV)

In Leviticus 23:5, the Passover, or Paschal Supper, and the Feast of Unleavened Bread, are plainly described as distinct feasts. See Exodus 12:6, Exodus 12:15, Exodus 12:17; Numbers 28:16–17.

(Leviticus 23:6) See Exodus 12:6. According to the Hebrew method of reckoning, the 15th day of the month began on the evening of the 14th. The day of holy convocation with which the Feast of Unleavened Bread began (Leviticus 23:7) was the 15th, and that with which it ended was the 21st .

(Leviticus 23:7) Feast – The three festivals (often called the Great Festivals)—Passover, Pentecost, and Tabernacles—to which the name חג (chag)—that is, a feast or rejoicing—properly belongs (Leviticus 23:6, Leviticus 23:34, Leviticus 23:39, Leviticus 23:41), were distinguished by the attendance of the male Israelites at the national sanctuary (Exodus 34:23; Deuteronomy 16:16).

In later times, they were called by the rabbis “pilgrimage feasts.” It is worthy of note that the Hebrew word is identical with the Arabic “haj,” the name of the pilgrimage to Mecca, from which comes the well-known word for a pilgrim, “haji.”

No servile work – literally, no work of labor, no work that belongs to one’s worldly calling, such as labor in agriculture or handicraft. The preparation of food was permitted (Exodus 12:16), a license not granted on the weekly Sabbath or on the Day of Atonement (Leviticus 23:28, Leviticus 23:30; Exodus 20:10; Exodus 35:3).

(Leviticus 23:8) The sacrifices meant here are named in Numbers 28:19-24.