What happened at Sinai in the Bible?
The mountain where God came down in fire and gave the law. "Mount Sinai was altogether on a smoke, because the LORD descended upon it in fire... and the whole mount quaked greatly" (Exod 19:18), and from it came the words that begin, "Thou shalt have no other gods before me" (Exod 20:3). The traditional site is Jebel Musa; the location is debated.