All of Israel had just agreed whole-heartedly to the covenant with the Lord. This was not a small deal so God called Moses into an exclusive executive meeting and gave him massive amounts of information including specific plans so Moses could construct a tent of meeting where God’s people would worship Him. The plans included instructions for the priests and described the items required inside the tabernacle too.
Moses was gone for over a month for this administrative meeting with God. He then came down the mountain with the first hard copy of the Ten Commandments, written on stone tablets. But while Moses was away, the people begged Aaron to give them “gods” they could see, so Aaron gave them what they wanted: a golden calf. The people chose to break the promises they had made to God and this made the Lord, and Moses, furious. God told Moses that He was going to destroy them all; however, Moses interceded on behalf of the Israelites. He demolished the god of gold and also broke the tablets of stone.
Moses then called those who were for the Lord to come to him and the tribe of Levi responded. With swords the Levites went through the camp killing 3,000 of the disobedient Israelites. Purity is not a small thing in the eyes of a holy God. I cannot begin to imagine the grief experienced in the camp that day. With great reverence to God, Moses spoke to the Levites, “Today you have ordained yourselves for the service of the LORD, for you obeyed him even though it meant killing your own sons and brothers. Today you have earned a blessing.” What a sobering experience. The blessing earned would not be quickly forgotten.