Most of us think of an idol as a statue of wood, stone, or metal worshiped by pagan people. But the concept is much broader and far more personal than that. An idol is anything apart from God that we depend on to be happy, fulfilled, or secure. In biblical terms it is something other than God that we set our heart on (Luke 12:29), that motivates us (1 Corinthians 4:5), that masters and rules us (Psalm 119:113; Ephesians 5:5), or that we trust, fear, or serve (Isaiah 42:17; Matthew 6:24; Luke 12:4-5). In short, it is something we love and pursue in place of God (see Philippians 3:19)
Given itis controlling effect on our lives, an idol can also be referred to as a “false god” or a “functional god.” As Martin Luther wrote, “To whatever we look for any good thing and for refuge in every need, that is what is meant by ‘god.’ To have a god is nothing else than to trust and believe in him from the heart…. To whatever you give your heart and entrust your being, that, I say is really your god.”
Even sincere Christians struggle with idolatry. We may believe in God and say we want to serve Him only, but at times we allow other influences to rule us. In this sense we are no different from the ancient Israelites: “Even while these people were worshiping the LORD, they were serving their idols. To this day their children and grandchildren continue to do as their fathers did” (2 Kings 17:41).
It is important to emphasize the fact that idols can arise from good desires as well as wicked desires. It is often not what we want that is the problem, but that we want it too much. For example, it is not unreasonable for a man to want a passionate sexual relationship with his wife, or for a wife to want open and honest communication with her husband, or for either of them to want a steadily growing savings account. These are good desires, but if they turn into demands that must be met in order for either spouse to be satisfied and fulfilled, they result in bitterness, resentment, or self-pity that can destroy a marriage.
Ken Sande and Tom Raabe, Peacemaking for Familes, p. 18-19
Luther quote from Luther’s Large Catechism by F. Samuel Janzow, p. 13