“a kingdom of priests.” When Israel got to Mount Sinai, God called Moses up onto the mountain and spoke with him (Exod. 19:3-6). God told Moses it was His intention to make Israel a kingdom of priests to all the other nations (v. 6), which meant that God intended for Israel to minister to the other nations and lead them to Yahweh. But God’s statement was conditional upon Israel obeying Him, and started out with “if you will listen.” God said, “if you will listen, yes, listen to my voice and keep my covenant, then you will be my own possession from among all peoples—for all the earth is mine—and you will be to me a kingdom of priests and a holy nation” (Exod. 19:5).
Things started out well. Moses led the people of Israel to the base of Mount Sinai (Exod. 19:17), and then God spoke the Ten Commandments in a loud voice from the top of the mountain (Exod. 20:1). The voice scared the people and they told Moses they did not want to hear God’s voice anymore, and that Moses could talk with God and then they would listen to Moses (Exod. 20:18-22). So God gave Moses the laws that are recorded in Exodus 21-23, and in Exodus 24:3-8, Moses told Israel what God had said. Then Moses followed that up by writing down the words God had said and he read them to the people. Israel twice stated that they would obey God (Exod. 24:3, 7), and they made a blood covenant with God that they would obey Him. Animals were sacrificed and the blood was caught in basins, and half the blood was put on God’s altar (Exod. 24:6), and half the blood was sprinkled on the people as a testimony of the covenant that they had made (Exod. 24:8). This covenant is the “Old Covenant,” usually called the “Old Testament.”
Sadly, it was only about a month later that Israel broke the first two of the Ten Commandments and all the laws God had given them about not worshiping pagan gods. They made a golden calf god and claimed it had brought them out of Egypt (Exod. 32:1-6). God and Moses were furious, and Moses called out, “Whoever is on Yahweh’s side, come to me!” At that point, “All the sons of Levi gathered themselves together to him” (Exod. 32:26). The Levites were bold in their defense of the worship of Yahweh and killed about 3,000 idolaters that day (Exod. 32:28).
The result of the unfaithfulness of the people of Israel was that God did not make them a kingdom of priests like He had intended, while the result of the faithfulness of the people of the tribe of Levi is that God chose them to minister as priests and Levites to Him (Num. 1:47-53).
[For more on God speaking the Ten Commandments directly to the Israelites, see commentary on Exodus 19:9. For more on Moses’ seven trips up and down Mount Sinai, see commentary on Exod. 19:3.]
“and a holy nation.” After Israel left Egypt, God stopped dealing with them as a family, the descendants of Abraham, Isaac, and Jacob, and began dealing with them as a nation, as He says here. Little is known about the time from Adam to after Noah’s Flood. It is over 1,600 years, yet it only takes 11 chapters in the Bible. In contrast, to cover the last 1,000 years of the Old Testament it takes all the books of the Bible from 2 Samuel through the Four Gospels and the time of Christ. From Seth until the Exodus the Bible follows the development of one family that goes from Seth through Abraham (Gen. 11:10-32), then Isaac and Jacob, then to Jacob’s 12 sons and their children, and ends with the Exodus. After the Exodus, God dealt with Israel as a nation (cp. Exod. 19:6).