An idol, or cult image, is an object that is worshiped as a god or in place of God, according to the Bible. God in His commandments forbids His people to create such idols or images to worship, since He considers that to be spiritual adultery (being unfaithful to God) in His eyes. In ancient religions, deities like the Canaanite Baal, the Phoenician Astarte, and the Egyptian Ptah were venerated with idols. In modern Christianity, the definition also extends to ideas or even people that are worshiped as a god or in place of God, other than the person of Jesus Christ.

In the Left Behind series, there is mention of idols being used by the people of other religions to worship during the Tribulation, up to the point where Nicolae Carpathia demanded exclusive worship of himself by the decree of the Global Community, at which point the only permitted idols become the various life-size statues of Carpathia erected in major cities, including the larger-than-life statue in New Babylon.

In the Left Behind timeline, the English usage of the word "idol" to mean a popular singer or entertainer has either faded from common use, or has never entered it, since the term is never used that way.

Psalm 115 alludes to idols, as it says that idols are anthropomorphic representations that are made by human hands, but they do not have the attributes of living creatures, since they cannot speak, walk, and smell. However, in the Left Behind series, the statue of Carpathia has the power to speak and may have the power to strike down those who refuse to bow in obeisance to it, although that ability might be credited to the False Prophet, Leon Fortunato. The statues often billow smoke, have its eyes turn red, and often quiver after a false messiah performs a miracle in the name of Nicolae Carpathia.

The ecumenical council of Enigma Babylon One World Faith allowed, but did not promote, the use of physical idols during worship.