Scripture is clear: Idols are nothing. However, the scriptures point out that it is not the physical manifestation of the idol nor the demonic forces it represents but the disaffection of peoples’ hearts from their Lord and Creator that is deadly.
In one of the more amusing Old Testament passages, the Prophet Isaiah shows the futility of idols by describing a man using half of a wooden log to warm himself and cook a meal and then worshipping the other half:
He cuts down cedars, or he chooses a cypress tree or an oak and lets it grow strong among the trees of the forest. He plants a cedar and the rain nourishes it. Then it becomes fuel for a man. He takes a part of it and warms himself; he kindles a fire and bakes bread. Also he makes a god and worships it; he makes it an idol and falls down before it. Half of it he burns in the fire. Over the half he eats meat; he roasts it and is satisfied. Also he warms himself and says, “Aha, I am warm, I have seen the fire!” And the rest of it he makes into a god, his idol, and falls down to it and worships it. He prays to it and says, “Deliver me, for you are my god! Isaiah 44:14-17 English Standard Version (ESV)
The Prophet Jeremiah says physical idols are mere inanimate articles of superstition:
Their idols are like scarecrows in a cucumber field,
and they cannot speak;
they have to be carried,
for they cannot walk.
Do not be afraid of them,
for they cannot do evil,
neither is it in them to do good.”
Jeremiah 10:5 (ESV)
The Prophet Ezekiel emphasizes what was true all along; idol worship is a question of a person’s heart disaffection from the Lord:
For any one of the house of Israel, or of the strangers who sojourn in Israel, who separates himself from me, taking his idols into his heart and putting the stumbling block of his iniquity before his face, and yet comes to a prophet to consult me through him, I the Lord will answer him myself. Ezekiel 14:7 (ESV)
John Calvin comments on this passage:
…He who caused his idols to ascend unto his heart, he who placed the stumbling block of his iniquity before his face, that is, was drowned in his own superstitions, so that his idols bore sway in his heart.
Lastly, he who is so forward in audacity that he did not conceal his wish to oppose the Almighty: if anyone, says he, came to a prophet to inquire of him in me, or my name, I will answer him. He [the Lord speaking through the prophet]…could no longer bear the hypocrites who deluded themselves so proudly. And certainly when they openly worshipped idols, and were [filled] with many superstitions, what audacity and pride it was to consult true prophets?
It is much the same as if a person should want only insult and rail at a physician, and not only load him with reproaches, but even spit in his face: and should afterwards go and ask his advice, saying, “What do you advise me to do? How must I be cured of this disease?” Such pride could not be borne between man and man…How then will God permit such reproaches to go unpunished?
The Apostle Paul addresses the question of idols directly:
Therefore, as to the eating of food offered to idols, we know that “an idol has no real existence,” and that “there is no God but one.” For although there may be so-called gods in heaven or on earth—as indeed there are many “gods” and many “lords”— yet for us there is one God, the Father, from whom are all things and for whom we exist, and one Lord, Jesus Christ, through whom are all things and through whom we exist. 1 Corinthians 8:4-6 (ESV)
Calvin disagrees with the translation no…existence:
…As to the words, Erasmus reads thus — “An idol has no existence.” I prefer the rendering of the old translation — an idol is nothing. For the argument is this — that an idol is nothing, inasmuch as there is but one God; for it follows admirably — “If there is no other God besides our God, then an idol is an empty dream, and mere vanity.” When he says — and there is none other God but one, I understand the conjunction [as giving this explanation].
For the reason why an idol is nothing is, that it must be estimated according to the thing that it represents. Now it is appointed for the purpose of representing God: nay more, for the purpose of representing false gods, inasmuch as there is but one God, who is invisible and incomprehensible.
The reason, too, must be carefully observed — An idol is nothing because there is no God but one; for he is the invisible God, and cannot be represented by a visible sign, so as to be worshipped through means of it. Whether, therefore, idols are erected to represent the true God, or false gods, it is in all cases a perverse contrivance.
Hence Habakkuk calls idols teachers of lies, (Habakkuk 2:18) because they deal falsely in pretending to give a figure or image of God, and deceive men under a false title. Hence οὐδεν (nothing) refers not to essence, but to quality — for an idol is made of some substance — either silver, or wood, or stone; but as God does not choose to be represented in this way, it is vanity and nothing as to meaning and use.
Paul takes it further and calls covetousness, which is a specific heart attitude, idolatry:
For you may be sure of this, that everyone who is sexually immoral or impure, or who is covetous (that is, an idolater), has no inheritance in the kingdom of Christ and God. Ephesians 5:5 (ESV)
Calvin points out this identification is representative of a greater issue:
Nor covetous man, who is an idolater. “Covetousness,” as he says in another place, “is idolatry,” (Colossians 3:5) — not the idolatry which is so frequently condemned in Scripture, but one of a different description. All covetous men must deny God, and put wealth in his place; such is their blind greediness of wretched gain.
But why does Paul attribute to covetousness alone what belongs equally to other carnal passions? In what respect is covetousness better entitled to this disgraceful name than ambition, or than a vain confidence in ourselves?
I answer, that this disease is widely spread, and not a few minds have caught the infection. Nay, it is not reckoned a disease, but receives, on the contrary, very general commendation. This accounts for the harshness of Paul’s language, which arose from a desire to tear from our hearts the false view.
Calvin says that all heart passions that disobey God deserve being labelled idolatry. But, he says, Paul is emphasizing covetousness because of its effect in man. As his Lord had said:
“No one can serve two masters, for either he will hate the one and love the other, or he will be devoted to the one and despise the other. You cannot serve God and money [or possessions].” Matthew 6:24 (ESV)
The same also recorded in Luke 16:13. Calvin draws an important distinction concerning this passage in Matthew:
…Christ affirms that it is impossible for any man to obey God, and, at the same time, to obey his own flesh…where riches hold the dominion of the heart, God has lost his authority. True, it is not impossible that those who are rich shall serve God; but whoever gives himself up as a slave to riches must abandon the service of God: for covetousness makes us the slaves of the devil.
…What is here said with a special reference to riches, may be properly extended to every other description of vice. As God pronounces everywhere such commendations of sincerity, and hates a double heart, (1 Chronicles 12:33; Psalm 12:2) all are deceived, who imagine that he will be satisfied with the half of their heart.
All, indeed, confess in words, that, where the affection is not entire, there is no true worship of God: but they deny it in fact, when they attempt to reconcile contradictions. “I shall not cease,” says an ambitious man, “to serve God, though I devote a great part of my mind to hunting after honors.”
It is, no doubt, true, that believers themselves are never so perfectly devoted to obedience to God, as not to be withdrawn from it by the sinful desires of the flesh. But as they groan under this wretched bondage, and are dissatisfied with themselves, and give nothing more than an unwilling and reluctant service to the flesh, they are not said to serve two masters.
For their desires and exertions are approved by the Lord, as if they rendered to him a perfect obedience. But this passage reproves the hypocrisy of those who flatter themselves in their vices, as if they could reconcile light and darkness.

Scarecrow, Japan Paddy Field, By FG2, released into the Public Domain by its author