Shabbat-

Shabbat is one the Saturday. Shabbat is the holiest day of the week. Some say it is the holiest day of the year. The people that say it is the holiest day of the year, bring a proof to what they say: On a regular Monday, and Thursday we read the Torah only 3 Aliyot. On a Rosh Chodesh, or Chol HaMoed we read 4 Aliyot. On Yom Tov we read 5 Aliyot. On Yom Kippur we read 6 Aliyot. On Shabbat we read 7 Aliyot. So that from they derive that Shabbat is the holiest of days. The 39 TORAH prohibitions on Shabbat, the work that they used to do in the Beit Hamikdash-1)Selecting. 2) Winnowing. 3) Threshing. 4)Gathering. 5)Cutting. 6)Plowing. 7)Planting. 8)Combing. 9)Bleaching. 10)Shearing. 11)Baking. 12)Kneading. 13)Sifting. 14)Grinding. 15)Tying. 16) Separating. 17)Weaving. 18)Threading Loom. 19)Threading Harness. 20) Spinning. 21)Coloring. 22)Tanning. 23)Slaughtering. 24)Trapping. 25)Tearing. 26)Sewing. 27)Untying. 28)Demolishing. 29) Building. 30)Erasing. 31)Skinning . 32)Writing. 33)Cutting to Shape. 34)Marking. 35)Smoothing. 36) Transferring objects, from public domain, to private domain. 37)Final Hammer Blow. 38)Put out fire. 39) Kindling a fire. There are many prohibitions from the Gemara, but these are called the "Av Melachot"-Father Melachot.