Deuteronomy 17:14–20 lays the foundation for the monarchy in Israel and the Davidic ruler, explaining that the only legitimate king of God’s people is the one who keeps His law. This law was revealed in shadowy form at Mt. Sinai under the terms of the old covenant, and Sinai is an important motif that we find developed throughout the Old Testament and fulfilled under the new covenant.
Sinai first appears in Exodus 3, although in that chapter it is called Mt. Horeb, which is another name by which the mountain is known. God first revealed Himself to Moses on Sinai, when He called him to go to the pharaoh, and it is Sinai to which the people of Israel came and received the Law after being liberated from Egyptian slavery. As such, Sinai could be considered the mountain of the Lord’s revelation, since our Creator disclosed Himself there.
In Exodus 19, Moses gives us an inspired account of what happened at Sinai when the Israelites arrived. God made His presence known on the beginning of the third day, descending as fire and enveloping the mountain in lightning, thunder, cloud and smoke (vv. 16–19). This was truly an awesome sight, and it was meant to remind the people that the sovereign who set them free was no deity to be taken lightly. Other passages of Scripture tell us that angels were also present (Gal. 3:19), their submission to the Lord being a further indication of His glory and power. God’s holiness is also a powerful motif in His appearance to the people at Sinai, as the need for the people to be purified is stressed. They are also forbidden to touch the mountain lest they be destroyed (Ex. 19:9b–15).
Even though God gave His people the Torah at Mt. Sinai, Exodus 19 also shows us how He remained hidden. As many commentators note, the presence of clouds and smoke indicate that our Lord concealed His full glory from the eyes of the people. God gave His commandments, but He did not tell us everything there is to know about Him. This is an important principle to remember, for we are to learn that the Lord has revealed only what we need to know and that we have no business prying into or speculating about things not disclosed to us. As Martin Luther says, “Wherever God hides Himself, and wills to be unknown to us, there we have no concern.”