Do Noahides Observe Special Holidays or Events?
UNIVERSAL HOLIDAYS
These holidays are all God-made days for human celebration, thanksgiving and rest:
SABBATH
The Sabbath, the week's seventh day (Saturday or, according to the ancient Hebrew reckoning, Friday night to Saturday night).
God blessed the Seventh day, and He declared it to be holy. - Genesis 2:3
We explore the phenomenon of the great gift of the Sabbath further in Should Noahides Keep the Sabbath?, The Sabbath and Holiness, Shabbat for the Universe, First Covenant Religion (and Maimonides).
NEW MOON
The first day of every (lunar) month - that is to say, the first day of the new moon (in Hebrew, Rosh Chodesh/Hodesh, or "Head of the Month"), when the first sliver of moon comes out. It helps to have a Hebrew or Jewish calendar - despite being one of the world's most ancient calendars, it's probably history's most accurate calendar (See Science and the Hebrew calendar ) - to identify the exact time and date of the New Moon.
It shall come to pass, that from one New Moon to another,
and from one Sabbath to another, all flesh
shall come to worship before Me, saith the Lord. - Isaiah 66:23
New Moons are representative of God's wisdom and awesome power, and the glory of Creation.
Getting a Hebrew calendar should be easy. Ask a Jewish friend or neighbor how to get one, get one free off the internet, or, if all else fails, go to your nearest Jewish bookstore - or to any of the many Judaica-selling sites on the internet - and get a big, beautiful one.
PILGRIMAGE FESTIVALS
Each of the four Hebrew pilgrimage festivals - Passover, or Pesach; Pentecost, or Shavuot ("Weeks"); Rosh HaShana, the New Year, including Yom Kippur, the Day of Atonement, 11 days later; Sukkot, or Tabernacles, the harvest festival - has tremendous universal significance and should be commemorated accordingly.
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PASSOVER
Passover recalls the history of Israel and the Gentile mixed multitude in Egypt, when the Lord, the God of freedom, humiliated the so-called gods of Egypt and "got honor" upon Himself by humbling both the slavemasters and their gods. With the Exodus, God spectacularly intervened in human history, to set men free from wickedness and slavery. The Exodus and the events surrounding it revealed God, HaShem, to the nations. This holiday, as Israel celebrates it, lasts for eight days (in the Land of Israel, seven days). That is, it always includes a day of the Sabbath.
Israel's celebration of Pesach always includes at least one seder celebration - an elaborate traditional meal and worship service. B'nai Noah have no obligation to do similarly - the seder, in essence, is a Jewish national celebration. Still, one would think that b'nai noah should celebrate the anniversary of the Exodus in some manner. Spectacularly and meaningfully, the Exodus and the events surrounding it revealed God, HaShem, to the nations. BThey may also attend a seder if Jewish seder to which they are invited.
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PENTECOST
Pentecost, 50 days after the beginning of Passover and the Exodus, commemorates the giving of the Torah: it's the anniversary of the day when God Himself first Revealed His Law and "spoke" to mankind at Sinai.
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NEW YEAR
Rosh HaShana, mankind's spiritual New Year - as opposed to the solar New Year, about the time of the winter solstice (January 1, a Christian holiday, is the assumed date of the circumcision or b'ris of Jesus, eight days after his supposed birthday on December 25th, or the night of the 24th) - falls at the end of the summer, in the northern hemisphere, on the first day of the new lunar month of Tishrei. This is a holiday of new beginnings.
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YOM KIPPUR
Yom Kippur, mankind's day of atonement, is connected to Rosh HaShanah.
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SUKKOT
Sukkot (sukkos) starts 15 days after Rosh HaShana. A sukkah is a booth, or casual dwelling, partially open to the rain and sun and the light from the stars; sukkot is simply the plural of sukkah. Israel celebrates this holiday for eight days - like the springtime Passover, which is related to Sukkot in many ways. This is one of the most explicitly universal of all the Torah holidays, as one sees from the traditional sacred readings connected with it.
In the Torah - specifically, in the Talmud, Avodah Zorah 3a - God challenges all the nations of the world to observe this "easy mitzvah," this easy commandment."
[Mitzvah, usually translated as commandment, or good deed, comes from a Hebrew root meaning "connection." To keep a commandment is to make a connection to God.]
One of the names of the holiday of Sukkot is the Feast of Tabernacles. See Zechariah 14:16-18: