23:3 seventh day is the sabbath. The weekly day of rest, commemorating God’s completed work of creation (Exodus 20:8-11), was even more sacred than the seven annual feasts. No “servile” work could be done in the latter (Leviticus 23:8,21,25,35,36), but no work at all on the sabbath. Also, no work could be performed on the great day of atonement (Leviticus 23:28).
23:4 feasts of the LORD. Many commentators, ancient and modern, have noted that these seven annual “feasts (or religious festivals) of Jehovah” not only had spiritual value to the Israelites who observed them but also gave prophetic witness to God’s great redemptive work as it would unfold throughout history. Note the order:
(1) Feast of the Passover (Leviticus 23:5) testifies of the shedding of the blood of the Lamb of God, “Christ our passover,...sacrificed for us” (I Corinthians 5:7).
(2) Feast of Unleavened Bread (Leviticus 23:6-8) speaks of the Lord’s supper, which would be instituted by Him on the night of the Passover and would serve to remind His followers again and again to walk in communion with Him. “Therefore let us keep the feast,...with the unleavened bread of sincerity and truth” (I Corinthians 5:8).
(3) Feast of Firstfruits (Leviticus 23:9-14) foreshadows the coming resurrection and restoration, “Christ the firstfruits; afterward they that are Christ’s at His coming” (I Corinthians 15:23).
(4) Feast of Pentecost (that is “fifty days”–Leviticus 23:15-22) was fulfilled in the descent of the Holy Spirit on the first body of Christian believers after Christ’s ascension, testifying to the world “that God hath made that same Jesus, whom ye have crucified, both Lord and Christ” (Acts 2:36).
(5) Feast of Trumpets (Leviticus 23:23-25) is separated by a long period of time from the first four festivals and promises that someday “the Lord Himself shall descend from heaven...with the trump of God,” when “the trumpet shall sound, and the dead shall be raised incorruptible” (I Thessalonians 4:16; I Corinthians 15:52).
(6) Day of Atonement (Leviticus 23:26-32) testifies of the certain judgments to come–on Israel, on the nations, on believers and on the lost–when complete separation between unforgiven sinners and perfected saints will be established forever (note the two goats in Leviticus 16, the chapter giving the details of this observance).
(7) Feast of Tabernacles (Leviticus 23:33-43) speaks of the coming eternal rest in the Holy City, when “the tabernacle of God is with men, and He will dwell with them, and they shall be His people” (Revelation 21:3).
23:16 fifty days. The Lord “came down” at Sinai on the fiftieth day after the first Passover (Exodus 12:6; 19:1, 11), just as the Holy Spirit came down fifty days after Christ’s crucifixion (Acts 1:3-4; 2:1-4).
23:24 blowing of trumpets. This day has been observed by the Jews as Rosh Hashanah, beginning the new year of the Jewish civil calendar.
23:27 day of atonement. The “day of atonement” is Yom Kippur in the Jewish calendar. The details of its divinely prescribed observance are given in Leviticus 16.