John Calvin is quoted as calling the human heart an idol factory (fabricum idolarum). He stressed that the propensity for idolatry is deeply rooted in the heart of sinful humanity.
Bright, however, as is the manifestation which God gives both of himself and his immortal kingdom in the mirror of his works, so great is our stupidity, so dull are we in regard to these bright manifestations, that we derive no benefit from them….but we are all alike in this, that we substitute monstrous fictions for the one living and true God….almost every man has had his own god. To the darkness of ignorance have been added presumption and wantonness, and hence there is scarcely an individual to be found without some idol or phantom as a substitute for Deity. Like water gushing forth from a large and copious spring, immense crowds of gods have issued from the human mind, every man giving himself full license, and devising some peculiar form of divinity, to met his own views.
Idolatry isn’t just wrong because it’s worshiping the creature, idolatry is wrong because it distorts and attacks the very character of God.
Paul speaks very directly to this issue in Romans 1 when he writes that idolatry consists of exchanging the glory of God for a lie, elevating the creature and denigrating the Creator:
Romans 1:22-25 “Claiming to be wise, they became fools, 23 and exchanged the glory of the immortal God for images resembling mortal man and birds and animals and creeping things. 24 Therefore God gave them up in the lusts of their hearts to impurity, to the dishonoring of their bodies among themselves, 25 because they exchanged the truth about God for a lie and worshiped and served the creature rather than the Creator, who is blessed forever! Amen.”
R.C. Sproul sums it up like this:
Any distortion of the character of God poisons the rest of our theology. The ultimate form of idolatry is humanism, which regards man as the measure of all things. Man is the primary concern, the central focus, the dominant motif of all forms of humanism. Its influence is so strong and pervasive that its seeks to infiltrate Christian theology at every point. Only by a rigorous attention and devotion to the biblical doctrine of God will we be able to keep from tasting and even swallowing this noxious brew.
May we not be the men and women who gargle the noxious brew of idolatry, but may we be the people who deny ourselves and give our utmost to a rigorous devotion of knowing the person and work of God with all our heart, soul, mind, and strength.
Information gathered from this book:
What is Reformed Theology? Understanding the Basics