I am a religious studies minor. I have seen the number seven appear in much of my reading about Judaism. In his book, "Night," Elie Wiesel says, "seven times cursed and seven times sealed." What is the meaning, significance and origin of the number seven in Judaism?

Answer

The following article on the Aish.com website, written by Rabbi
Yaakov Salomon, should answer your question:

In the beginning... God created 7's.

Oh sure, He created light and dark, the heavens and earth, too.
But for reasons unknown to us, He seemed to have a special
affinity for the number 7.

The fact that the Torah begins with a verse containing 7 words
and 28 letters (divisible by 7) is hardly remarkable. But when
placed within the context of the overwhelming number of
associations in Judaism with '7', a fascinating tapestry begins
to unfurl. Let's take a closer look at this phenomenon.

Every spring, Jews around the world celebrate the holiday of
Shavuot --commemorating the most seminal event in the history of
mankind, God's revelation at Mount Sinai.

Shavuot. Curious name for this holiday, no? Shavuot means
"weeks," underscoring the 7-week period between Passover and
Shavuot in which we count each day (and week) in anticipation and
preparation for re-living the Sinai revelation. But why call it
Shavuot -- "weeks"? Why not call the holiday "Torah," or "Sinai,"
or "Commandments," or "Tablets." Of what significance is "Weeks"?

Time contains many different entities. Nearly all of them are
related to natural phenomena. Days, nights, months, seasons and
years are all directly determined, in some way, by the
constellations. There is one exception -- the week. The
formulation of a week seems to be totally arbitrary. Who needs
it? Let one day just follow the previous one. And why 7 days?

The concept of a week and its constitution of 7 days is one that
is strictly God-invented and human-adopted. While we may quibble
about creation -- how, when, by whom, why -- the world has
consensually agreed to the concept of a week. The Beatles were
wrong... there are only 7 days in a week. And whenever a week is
completed it is yet another reminder to mankind (or should be)
that God created the world in 7 days. (Only 6 days were required
to manufacture the physical structures, but the process was not
complete until the spiritual realm, Shabbat, was added.)

Call it the "week link."

Kabbalah teaches that 7 represents wholeness and completion.
After 7 days, the world was complete. There are 6 directions in
our world: north, south, east, west, up and down. Add to that the
place where you are, and you have a total of 7 points of
reference.

Shavuot, marking the emergence of the Jewish people into a
nation, by virtue of their receiving and accepting the Torah,
also marks a completion. Perhaps that is why the holiday is
called Shavuot, "Weeks." We want to identify this holiday as a
completion of the process of Jewish nationhood.

No one is certain why God chose the number "7" to signify
completion. All we can do is speculate, observe and marvel.

In honor of our own completion of the 49 day period leading up to
Shavuot, we present 49 allusions to the number "7" within
Judaism. How many of these do you recognize? How many more can
you add?

1. Shabbat is the 7th day of the week.
2. There are 7 weeks in the counting of the Omer before
Shavuot. (Leviticus 23:15)
3. In Israel, there are 7 days of Passover and Sukkot.
(Leviticus 23:6, 34)
4. Every 7th year, the land lays fallow during Shmita
(Sabbatical year). (Leviticus 25:4)
5. After 7 cycles of Shmita, we have a Jubilee year (Yovel).
(Leviticus 25:8)
6. When a close relative dies, we sit Shiva for 7 days.
7. On Sukkot we shake 7 species - 1 Lulav, 1 Esrog, 2 willows,
and 3 myrtles.
8. Yitro, the first real convert to Judaism, had 7 different
names, and 7 daughters (one who married Moses).
9. Moses was born and died on the same day - the 7th of Adar.
10. Our Sukkah huts are "visited" by 7 guests - Abraham, Isaac,
Jacob, Moses, Aaron, Joseph and David.
11. The Menorah in the Temple had 7 branches.
12. Achashvarosh, King of Persia during the miracle of Purim,
held a party for 7 days. (Esther 1:5)
13. There are 7 holidays in the Jewish year: Rosh Hashana, Yom
Kippur, Sukkot, Chanukah, Purim, Passover, and Shavuot.
14. In addition to the 613 Commandments, the Sages added 7
more.
15. There are 7 Noachide Laws pertaining to all humanity.
16. At every Jewish wedding, 7 blessings are recited (Sheva
Brachot).
17. Each Shabbat, 7 people are called to the Torah reading
(Aliyot).
18. The first verse in the Torah contains 7 words (and 28
letters).
19. Our Matriarch Leah had 7 children - six sons and one
daughter.
20. There were 7 days of preparation for the construction of
the Tabernacle in the desert. (Leviticus 8:35)
21. Traditionally, the bride circles the groom 7 times under
the Chuppah (wedding canopy).
22. We wind the Tefillin straps around the arm 7 times.
23. Moses was the 7th generation after Abraham.
24. Each plague in Egypt lasted 7 days.
25. In Pharaoh's dreams there were 7 cows and 7 stalks of
grain. (Genesis 41)
26. The Biblical contamination period typically lasts 7 days.
(Leviticus 13:4)
27. God created 7 levels of heaven. (Hence the expression, "I'm
in 7th heaven!")
28. On Shabbat and holidays, we recite 7 blessings in the
silent Amidah.
29. There are 7 special species of produce by which the Land of
Israel is praised: wheat, barley, grapes, pomegranates, figs,
olives, and dates. (Deut. 8:8)
30. The world has 7 continents.
31. The 7 weeks of the Omer correspond to the 7 "sefirot," the
7 behavior traits in which we serve God: kindness, strength,
beauty, triumph, splendor, foundation, and kingship.
32. Noah sent the dove and the raven out of the Ark for 7 days
to inspect the weather conditions. (Genesis 8:10)
33. 7 nations warred with Israel: Canaanites, Hittites,
Hivites, Amorites, Perizzites, Jebusites, and Girgashites.
34. On Yom Kippur, the High Priest sprinkled the blood in the
Temple 7 times. (Leviticus 16)
35. The Jewish New Year of Rosh Hashana occurs, surprisingly,
in the 7th month -- Tishrei. (Leviticus 23:24)
36. The Jewish calendar, largely lunar, has a cycle of
intercalation that contains 7 leap years during each 19-year
period.
37. There are 7 notes on the musical scale.
38. A Kohen (priest) should participate in the burial of 7
relatives: father, mother, sister, brother, son, daughter, and
spouse. (Leviticus 21:2)
39. We dance 7 circles (hakafot) on the holiday of Simchat
Torah.
40. The smallest allowable dimension of a Sukkah is 7 by 7
handbreadths.
41. The world has 7 seas.
42. Joshua led the Jewish People around the walls of Jericho 7
times before the walls fell. (Joshua 6:15)
43. Jacob worked for Laban for 7 years (twice) in order to
marry his daughters. (Genesis 29:27)
44. The Holy Temple contained 7 gates of entry.
45. We recite 7 blessings every day before and after the
"Shema" -- 3 in the morning and 4 at night.
46. The Talmud lists 7 female prophets: Sarah, Miriam, Deborah,
Hannah, Avigail, Chuldah, and Esther.
47. A Jewish servant regains freedom in the 7th year. (Exodus
21:2)
48. We conclude our Yom Kippur prayers by proclaiming7 times,
"The Lord is God!"
49. A Jewish wedding is followed by 7 days of celebration
(Sheva Brachot).