Moses assigned Joshua to lead the able men out to fight against the Amalekites. Moses stood on top of a hill. While he held up his arm with his staff, Israel prevailed. But when Moses let his arm down, Amalek prevailed. So Aaron and Hur propped up Moses' arm with his outstretched staff, and Israel defeated the Amalekites. (Exodus 17:8-13)
Moses led the people to Mount Horeb, which is Sinai, and they camped there for the duration of the events recorded in the book of Exodus, which documents Moses' times on the mountain. During this period, Moses received the Ten Commandments and various laws and ordinances, and the divine design and construction of both the Ark of the Covenant and the Tabernacle of Meeting, a prototype of the temple, which would be built 480 years later.
When Moses ascended the mountain to meet with God, God first told Moses to tell the people of Israel His grand plan. “You have seen what I did to the Egyptians, and how I bore you on eagles' wings and brought you to Myself. Now therefore, if you will indeed obey My voice and keep My covenant, then you shall be a special treasure to Me above all people; for all the earth is Mine. And you shall be to Me a kingdom of priests and a holy nation.”
Moses came down and gathered the elders of the people and shared with them all God had said to him. They answered Moses, “All that the LORD has spoken we will do.” Then Moses returned to the mountain to bring back the words of the people to the Lord. Throughout this entire time, Moses ascended and descended the mountain seven times. It was during his fifth time upon the mountain that Moses stayed 40 days and 40 nights. (Exodus 19:3-8)
This 40-day stretch on the mountain unsettled the people. They came to Aaron and demanded that he make them a visible, tangible god, like the ones they had known in Egypt. “Come, make us gods that shall go before us; for as for this Moses, the man who brought us up out of the land of Egypt, we do not know what has become of him.” (Exodus 32:1)
Aaron had them bring all their golden earrings. He melted down the gold and fashioned it into a calf. He built an altar and proclaimed a feast. The next day, the people offered sacrifices to the gold calf, ate, drank and “indulged in revelry,” as the NIV and NLT translate it, or, as the New Century Version has it, “they got up and sinned sexually.” The KJV and NKJV translate it “rose up to play.” Clearly, there was more going on than just a potluck picnic.
Meanwhile, Moses was receiving the details of the Law, the Ark and the Tabernacle. Suddenly, God told Moses to get back to camp, and told him why. Further, the Lord told Moses, “I have seen this people, and indeed it is a stiff-necked people.” God, His longsuffering almost at its end, was ready to put a quick end to Israel and to begin afresh with Moses. But Moses humbly and distraughtly interceded for the Israelites, as if to remind God of His promises to Abraham, Isaac and Jacob. This shows an aspect of God that few grasp; a final point when mercy and patience is ever-so-close to the end. Scripture states that God “relented from the harm which He said He would do to His people.” (Exodus 32:9, 14)
Moses returned from the mountain with the two tablets in his hands, and as he came near the camp, he saw the calf and many people dancing around naked. Moses was so angry that he threw down the stone tablets and they broke in pieces. He took the calf, burned it in the fire, ground it to powder, scattered the powder on the water and made the people drink it. He confronted Aaron, who hastily shifted the blame entirely to the people. Moses demanded an immediate decision and commitment, “Whoever is on the LORD's side, come to me!” The Levites responded. Following Moses' command, they executed about 3,000 men. (Exodus 32:26-28)
Psalm 106 recounts these events, and how the Israelites “forgot God their Savior, Who had done great things in Egypt. Therefore He said that He would destroy them, had not Moses His chosen one stood before Him in the breach, to turn away His wrath, lest He destroy them.” This would not be the last time Moses would intercede for Israel.