The golden calf

Exodus 32:2 Now when the people saw that Moses delayed coming down from the mountain, the people gathered together to Aaron, and said to him, “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.” And Aaron said to them, “Break off the golden earrings which are in the ears of your wives, your sons, and your daughters, and bring them to me.” So all the people broke off the golden ear-rings which were in their ears, and brought them to Aaron. And he received the gold from their hand, and he fashioned it with an engraving tool, and made a molded calf.

Israel’s basic problem was impatience, an inability to wait, trust, and rest, which led to making something happen that would pass for God, a stand-in. It was the same old story of ‘Is God really with us or not?’ People do not like to have to live in the world of the unseen (faith that God is at work). They want to see some material evidence of God’s power, so they became impatient and made themselves a god. Feverish activity acts against real faith (God acting on our behalf). We build some kind of image, whether it be a system, or method or anything that can be a substitute for what only God can do.

Exodus 32:4 Then they said, “This is your god, O Israel, that brought you out of the land of Egypt!”
The golden calf was not meant to be another god. It actually represented God, Yahweh, on their terms. They proclaimed a ‘sacred feast’ to Yahweh, not just to a golden calf. Their concept was shaped by their past experience. They fashioned what was the 'sacred cow' of Egypt, a golden calf (or golden bull). People tend to seek empowerment from the power symbol that helped shape their concept of power/authority. Israel never fully overcame idolatry, and it remains as mankind’s problem to this day. Christians of all cultures are often not sure whether it is God or money that they trust.

God said He was a jealous God. His jealousy is the aggressive side of His love and protectiveness, and He will destroy all other gods that are put before Him, as He had Moses destroy the golden calf. God judged Israel with a plague and showed His hatred for Idolatry
“I will destroy them, and I will make you alone into a great nation." (Moses a type of Jesus’ sacrifice)

We become like what we worship.
Psalm 135:15-18 (puts it perfectly).
15. The idols of the nations are silver and gold, the work of men's hands. 16. They have mouths, but they do not speak; they have eyes, but they do not see; 17. They have ears but they do not hear; Nor is there any breath in their mouths. 18. Those who make them are like them; So is everyone who trusts in them.

We are given God to worship in spirit and in truth so that we will become like him. (His terms)
John 4:21 Jesus said to her, “Woman, You worship what you do not know; we know what we worship, for salvation is of the Jews. But the hour is coming, and now is, when the true worshipers will worship the Father in spirit and truth; for the Father is seeking such to worship Him. God is Spirit, and those who worship Him must worship in spirit and truth.”
Worship is an elevated way of declaring love. Human nature wants to put something on a pedestal. The moment you put God there and present yourself to him at the altar of your heart you are touching heaven. Romans 12:1-2