The Golden Calf
When Moses did not return from forty days and nights on Mount Sinai, the people gathered and demanded of Aaron, "make us gods to go before us," and Aaron collected their gold jewelry and cast a golden calf, which the people called the god that had led them out of Egypt. Coming down and seeing this, Moses smashed the tablets of the Ten Commandments in anger. This episode is often cited in discussions of "the wavering of faith under group pressure."