First and foremost it is important to observe that the giving of the law comes after the Exodus salvation event. Thus under the Old and New Covenants a major reason for the law is to know how to display an attitude of gratitude for salvation. The people are not given the law in order to earn salvation. They were saved by what God did for them. Thus the theme: “You yourselves have seen what I did to the Egyptians” (Exo 19:4). Their response is to obey his law so that they may be used to the end God desires. That is, as a kingdom of priests to intercede for the nations the way that Moses intercedes for Israel (Exo 19:5, cf. 1 Peter 2:4-10). Chapter 19 is the prelude to and preparation for the giving of the Ten Commandments.
The people are being set apart as the treasured possession of God among the nations upon the condition of obedience (Exo 19:5). Here we are to see similarity with the conditional covenant with Abraham (see discussion on Book Six). This is a conditional covenant they ultimately would not keep, but the unconditional covenant with Abraham would continue. Like they would later when ratifying the covenant (i.e. Josh 24:18), the people here (Exo 19:8) and later in this section (Exo 24:3, 7) say that they will do all the words of the LORD.
Note the context of the giving of the Ten Commandments. God is coming down in a thick cloud onto the mountain. The people hear the Ten Commandments from God speaking from heaven. Therefore, the people had to prepare spiritually — ritually for his coming. Anyone who touches the mountain without authorization from God will die (Exo 19:12). The people stand at the foot of the mountain to meet God and hear the Ten Commandments (Exo 19:17). The sound of the LORD is thunder — the sound of a huge army. This reminds us of the terror of The Day back in Genesis 3 when God came down on Mount Eden. Only Moses and Aaron are able to go up on the mountain at this point. And God spoke. The people will respond by noting their need for a mediator (Exo 20:19).
And God establishes the covenant — a treaty with his vassal nation. It follows the normal ancient near eastern treaty format. God introduces himself and gives a historical prologue (Exo 20:2). And then lays out the ten stipulations of the covenant. This is a summary of the law. The Reformed understanding of how to number the commandments highlights idolatry (Exo 20:4-6) as a separate commandment from the first (Exo 20:3). Thus the commandment concerning idolatry deals with how we worship whereas the first commandment concerns who we worship. As a summary of the laws regarding how we worship, this is the most serious example. But it represents all of the regulations of worship in Scripture. This shows why Reformed theology is concerned that we only worship God as He has revealed that He desires to be worshiped in His word. Other traditions have to divide up the commandment on coveting to count to ten and are more open to including man-made traditions in worship. It is significant that there are TEN — the number of fullness.
These commandments point us back to the salvation from Egypt and to creation. These commandments are a summary of the moral law of the covenant of creation. That the first commandment (Exo 20:3) was in force at the time of creation is beyond dispute. The Westminster Standards note that “before me” (Exo 20:3) means in the presence of the true God. The plagues and Exodus event showed that the LORD was greater than all other gods. The LORD is the God who created the heavens and the earth (Gen 2:4). The second commandment (Exo 20:4-6) points us to creation because humankind is made in the image of God (Gen 1:27). This is why the LORD could come as a person — Jesus. This is why we are not to make images of God. Note the contrast of generations under curse (three and four) with those showing loyal-love (thousands) (Exo 20:5-6).
I will not demonstrate each commandment in this manner, but know that all of them point us back to creation. The Ten Commandments, as related here in Exodus, does this explicitly with the Sabbath (“for in six days the LORD made heaven and earth, the sea…” Exo 20:11). The next commandment points us forward to the Promised Land (Exo 20:12). These are the conditional covenant stipulations for remaining in the land as a kingdom of priests. We have shown elsewhere that the commandment regarding adultery arises from creation. The commandment regarding murder points us to the same issues as the second commandment — we are made in the image of God.
The Book of the Covenant (Exo 20:22-23:19) follows the Ten Commandments. And the theme is that the people have seen that the LORD spoke to them from heaven (Exo 20:22). Enns notes in his commentary (pp.440-441) that the Book follows a pattern beginning with worship (Exo 20:22-26), then social responsibility (Exo 21:1-22:17), then worship and social responsibility (Exo 22:18-23:19). These laws are not exhaustive but representative of the legal code of Israel. They cover such things as (worship) idols and altars, (social responsibility) slavery, injuring others, injuries from animals, and personal property. And the final section with both alternates worship, social responsibility, worship, social responsibility, worship (note that it begins and ends with worship). Loving God and loving your neighbor are thus shown to be intricately related. The last social responsibility section ends with the law about not oppressing a sojourner because you were sojourners in Egypt (Exo 23:9).
Then the text changes focus to the conquest of the Promised Land (Exo 23:20-33). The primary reason for destroying the people in the land is so that they will not cause Israel to sin and thus keep Israel from being a blessing to the nations. Sending terror before Israel and hornets before Israel are parallel ideas (Exo 23:27-28). These are not literal hornets — the idea is that the people will stand in dread of invading Israel.
And this section ends with the seventy (ten times seven) elders of Israel hearing the Book of the Covenant and seeing God on the mountain (Exo 24:10) and having a covenant meal together (Exo 24:11). Almost makes one think of Passover as the unconditional covenant meal and this meal on the mountain as the conditional covenant meal. And Moses went up on the mountain to receive the Ten Commandments in written form. There is a Sabbath pattern (Exo 24:16) and Moses was on the mountain for a highly significant forty days and forty nights (Exo 24:18). Temptation time.