Psalm 106:20-21 They exchanged their Glory for an image of a bull which eats grass. They forgot the God who saved them who had done great things in Egypt.
The author of the psalm is talking about the Israelites after they were freed from slavery in Egypt by God. They had seen wonder after wonder, miracle after miracle performed By God.
Plaques against Egypt
Firstborn of Egypt killed, theirs spared.
Parting of Red Sea
Water from rocks
Manna from heaven
Victories against enemies
and so much more
Yet what did they do? They started worshipping a bull - an animal - something beneath them - a beast of burden - something that could not talk, something that cannot provide them will all their needs.
We look back and think of their "silliness" with it all but aren't we the same way? An idol is anything that takes the place of God in one's life.
We are all guilty of it - it doesn't have to be a bull, cow, statue, pole. It could be a job, hobby, car, boat, person, alcohol, cigarettes, drugs, shopping, possessions, etc.
Don't exchange the Glory of God for anything else. Remember what he has done, remember who he is.
And Worship him and only him.