What does Acts 7:39 mean?
Stephen has argued that God chose the Israelites as His people outside of the formally-established nation of Israel (Acts 7:2, 34). Later, he will show they worship a temple that could never hold God (Acts 7:44–50) and that they reject God's prophets (Acts 7:51–53), up to and including Jesus. In this section, Stephen reminds them that the Mosaic law which they claim to revere so faithfully has always been a stumbling block to their people.Here, Stephen is giving the account of the forty days when Moses climbed Mount Sinai to receive the Law from God while the Israelites below pushed Aaron to make a golden calf to worship. It seems the Israelites "turned to Egypt" by worshiping the Egyptian god Apis, which was associated with fertility. Apis took the form of a bull with a solar disk and vipers between his horns. The bull god was not unique to Egypt. Moloch, the Canaanite god, took the form of a bull; the ancient Akkadians had Gugalanna, the "Bull of Heaven;" and even today, rooftops in Peru often have small statues of bulls on either side of a Christian cross.
The Israelites also longed for the food (Numbers 11:5; 20:3–5) and water (Exodus 17:1–3) they had in Egypt. Moses promised the Israelites he would lead them to freedom and blessing if they only followed him. His successor, Jesus (Acts 7:37), promises the same to Stephen's audience. Stephen's accusers claim to honor the law Moses gave (Acts 6:11) when they really follow in the footsteps of the Israelites who rejected that Law.