The Israelite under the Law of Moses had physical sacrifices he was to make as part of his worship of God. One of the greatest sins an Israelite could do was to fall into idolatry, the worshipping of a foreign god, an idol; this is a sin which the nation fell into time and time again. Why was it so bad? God declares,
“You shall not follow other gods, any of the gods of the peoples who surround you, for the LORD your God in the midst of you is a jealous God; otherwise the anger of the LORD your God will be kindled against you, and He will wipe you off the face of the earth,” Deuteronomy 6:14-15.
God is a jealous God; His jealousy comes in when we give to another what is due to Him. The Israelite had a relationship with Him, but time and again, they gave their affections to idols, and not to Him, the One to whom it was due.
The Christian has sacrifices which he is required to make (see Sacrifices of the Christian Life). Can he also fall into idolatry? Obviously, if the Christian were to begin to worship an idol, he would be idolatrous. But is there another idolatry the Christian needs to be on guard against?
“For this you know, that no…covetous man, who is an idolater, has any inheritance in the kingdom of Christ and God,” Ephesians 5:5, and again,
“Therefore put to death your members which are on the earth…and covetousness, which is idolatry,” Colossians 3:5
The Scriptures identifies covetousness (or, greed) as idolatry. When a Christian has his mind set on earthly things, when his desire for earthly things has exceeded his desire for Christ, he has become an idolator. At that point, he has turned his affections from Christ, and turned them towards the things of this world. And as Ephesians plainly states, if we fall into this, we have no inheritance with Christ.
“Do not lay up for yourselves treasures on earth, where moth and rust destroy and where thieves break in and steal; but lay up for yourselves treasures in heaven, where neither moth nor rust destroys and where thieves do not break in and steal. For where your treasure is, there your heart will be also,” Matthew 6:19-21.