The Biblical Mount Sinai is an ambiguously located mountain at which the Old Testament states that the Torah were given to Moses by God. In certain biblical passages these events are described as having transpired at Mount Horeb, but though there is a small body of opinion that Sinai and Horeb were different locations, they are generally considered to have been different names for the same place.
According to the Biblical account of the law-giving, Sinai was enveloped in a cloud, it quaked and was filled with smoke, while lightning-flashes shot forth, and the roar of thunder mingled with the blasts of a trumpet; the account later adds that fire was seen burning at the summit of the mountain. Several scholars have indicated that it seems to suggest that Sinai was a volcano, although there is no mention of ash; other scholars have suggested that the description fits a storm, especially as the Song of Deborah seems to allude to rain having occurred at the time, with the fire possibly being some natural plasma effect.
In the Biblical account, the fire and clouds are a direct consequence of the arrival of God upon the mountain. In a midrash it is argued that God was accompanied by 22000 archangels, and 22000 divine chariots, and in order for all these to fit these onto the mountain, God made the mountain expand from its earlier size. The biblical description of God's descent superficially seems to be in conflict with the statement shortly after that God spoke to the Israelites from heaven; while textual scholars argue that these passages simply have come from different sources, the Mekhilta argues that God had lowered the heavens and spread them over Sinai, and the Pirke De-Rabbi Eliezer argues that a hole was torn in the heavens, and Sinai was torn away from the earth and the summit pushed through the hole...