We tend to think of idolatry as something they did in Old Testament times, but can believers today still commit idolatry?
Old Testament Idolatry
When God gave Israel the Ten Commandments, they began with the command to worship no other gods, including those which are simply carved or molten images. God commands, “You shall not make for yourself a carved image, or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth. You shall not bow down to them or serve them, for I the LORD your God am a jealous God, visiting the iniquity of the fathers on the children to the third and the fourth generation of those who hate me, but showing steadfast love to thousands of those who love me and keep my commandments” (Ex 20:4-6), and this meant, “You shall have no other gods before me” (Ex 20:3). Clearly, anything that comes before God is an idol, and for Israel it was often their thirst or hunger. That’s why they would often grumble against Moses, but as we know, when they grumbled against Moses, they were actually grumbling against God. In one case, “the whole congregation of the people of Israel grumbled against Moses and Aaron in the wilderness, and the people of Israel said to them, “Would that we had died by the hand of the LORD in the land of Egypt, when we sat by the meat pots and ate bread to the full, for you have brought us out into this wilderness to kill this whole assembly with hunger” (Ex 16:2-3), and so “They murmured in their tents, and did not obey the voice of the LORD” (Psalm 106:25), and thus, they did not enter the Promised Land. Idolatry has its price. Later, it would cause the nation to be taken into captivity.
The reason God wanted the Israelites to avoid mixing and marrying with the pagan nations around them was because they would eventually adopt the pagan religious practices of the pagan nations that surrounded them. History proved that when Israel began mixing with the nations, they began to adopt the pagan practices of those nations. It is in this context that the Apostle Paul says, “Do not be deceived: “Bad company ruins good morals” (1 Cor 15:33). Light has no business with the works of darkness. King Solomon married a foreign woman, and what was the result? It says “when Solomon was old his wives turned away his heart after other gods, and his heart was not wholly true to the LORD his God, as was the heart of David his father” (1 Kings 11:4), and “Solomon went after Ashtoreth the goddess of the Sidonians, and after Milcom the abomination of the Ammonites” (1 Kings 11:5). It’s bad enough worshipping a false god, and by the way, one that doesn’t even exist, but these pagan religions lead Israel so far from the path of God that, in just a few generations, they would actually be sacrificing their own children in the fire. And in a way, parents who’s frivolous lifestyle leads them to the negligence of their children’s upbringing, will also lead their own children into the same path…worshipping things rather than God.
When marriages are unequally yoked, with a believer and non-believer, it is like mixing with a pagan nation with a godly nation, in the sense that one will have their own god, while the other will try to worship the One, True God. A family cannot easily worship two different gods, and eventually, one will replace the other…and it could be the pagan religion of possessions that takes precedence. King Ahaz shows just how far our idolatrous hearts can carry us. It was when “Ahaz was twenty years old when he began to reign, and he reigned sixteen years in Jerusalem. And he did not do what was right in the eyes of the LORD his God, as his father David had done” (2 Kings 16:2), and what was the result of his idolatrous worship? It says “he walked in the way of the kings of Israel. He even burned his son as an offering, according to the despicable practices of the nations whom the LORD drove out before the people of Israel” (2 Kings 16:3). Just look how far they can draw us away from God!
Icons and Images
Some are persuaded that religious icons or images, particularly of certain saints, is a form of idolatry, because some pray to Mary or even Joseph, and confess their sins to a priest rather than to God as we’re commanded to do (1 John 1:9), but even so, there are those who put their trust in Christ and not in deceased saints or images. Just as there are false converts in Catholicism, there are false converts in Protestant churches, but in those same churches, they are many who are saved. Thankfully, we’re not saved if we don’t have perfect biblical understanding. God’s grace extends far beyond than anything we can image. He covers not just our sins, but our faults, weaknesses, misunderstandings, and mistakes, but the one mistake we don’t want to make is to put things or people in front of God. A man or woman who is a believer must not marry outside of the Body of Christ. It can lead to a bad marriage and a messy divorce, and no one wins in that situation! Marrying someone just because you love them is a form of idolatry if that person is not a believer. God is the One we must obey over humans (Acts 5:29), and obeying God includes putting Him before our own feelings. Years ago, as part of our self-examination before the Lord’s Supper, I suggested the church log their time spent during the week. How many hours did they pray? When and how often? When did they read their Bible? Outside of work and child care, how much of their free time was spent watching TV or on the Internet compared to that spent in prayer and Bible study? Some later told me they felt liked they’d been punched in the gut. I told them the Word of God cuts like a double-edged sword, but I told them, “It cuts me before it cuts you!” (Heb 4:12), meaning, I’m fodder for the Word of God just as much as they are. And by the way, I didn’t do so well either. The point being, we can shape, form, or chisel just about anything out of whatever it is that takes up our time and money. What or who is it that you most treasure? The only reason I ask that because “where your treasure is, there your heart will be also” (Matt 6:21).
I think you can see that all of us are prone to having idols. Yours might not be the same as mine, but if it qualifies as an idol, that is, if it’s taking precedence in our life and altering our decisions in life, then it is an idol. It must be smashed but it can only be done by throwing yourself on the mercy of God. Ask Him to help you slay the idol in your (and my) heart. Anything or anyone that is placed before God is an idol, and as we know, our hearts are truly idol factories.
Here is some related reading for you: 10 Idols Of Your Heart To Remove 
Resource – Scripture quotations are from The Holy Bible, English Standard Version® (ESV®), Crossway Bibles. (2007). ESV: Study Bible : English standard version. Wheaton, Ill: Crossway Bibles. Used by permission. All rights reserved.