Did Aaron, the first high priest of Israel, believe in God? Most certainly, and his faith was very personal.
Moses and Aaron, Nadab, and Abihu, and seventy of the elders of Israel went up, and they saw the God of Israel. There was under His feet as it were a pavement of sapphire stone, like the very heaven for clearness. And He did not lay His hand on the chief men of the people of Israel; they beheld God, and ate and drank (Exodus 24:9-11).
How appropriate for Aaron, the first priestly link between God and Israel, to know the God he would represent (Exodus 28:1; 30:30). Aaron, with all the people, heard God’s voice declare the Ten Commandments, beginning with decrees against idolatry (Exodus 20:3-4, 18-23). How, then, can we account for Aaron building the golden calf in the very shadow of Mount Sinai? Aaron knew better! There can hardly be a stronger faith than the fresh memory of direct experience (cf. John 20:24-29). Aaron had a wonderful basis for knowledge and faith. What he lacked was the willpower to do what he knew. When the people pressed him, he gave in and led them in idolatry (Exodus 32:1-35). Yet still Aaron acknowledged Yahweh, the true God he knew. The people saw the golden calf as representing their “gods.” Aaron’s reaction shows that he planned to honor the LORD (YHWH or Yahweh).
[When the people saw Aaron’s golden calf,] they said, “These are your gods, O Israel, who brought you up out of the land of Egypt!” When Aaron saw this, he built an altar before it. And Aaron made proclamation and said, “Tomorrow shall be a feast to the LORD” (Exodus 32:4-5).
Aaron knew better but he lacked willpower.
Here, in the midst of this rebellion, was a form of faith. God was anything but pleased.
They have turned aside quickly out of the way that I commanded them…. Now therefore let Me alone, that My wrath may burn hot against them and I may consume them (Exodus 32:8, 10).
Aaron was spared, not because of his “feast to the LORD,” but because Moses interceded on his behalf (Exodus 32:11-14; Deuteronomy 9:19-20).