In recent years there has been something of a recovery of the relevance of idolatry to practical Christian living and pastoral care. I deliberately say recovery, or rediscovery, for one can find this train of thought in Calvin, Luther and Cranmer.
The following is taken from Cranmer's Catechismus, or to give it it's full title:
that is to say, A Short Instruction Into Christian Religion,
for the singular commodity and profit of children and young people:
set forth by the most reverend father in God,
Thomas, Archbishop of Canterbury, Primate of all England, and Metropolitan (1548).
...by fearing, by trusting, and by loving, we may easily make a god out of a creature, which indeed is no god, but rather an idol, set up by our own fancy. But this is a horrible sin against the first commandment of God, and so much the more perilous, because it lurks in the corners of man's heart most secretly.
When a man fears any creature, and thinks thus with himself, 'If such a thing be taken away from me; if such a great man be angry with me; if I escape not such a danger, then I am utterly undone, then I know not whither to run for aid and succour. Whither then shall I go? Who shall save or help me?
If thou have any such thought of any creature truly in thy heart, thou makest it a god, although with thy mouth thou dost not call it a god. And this affection lies lurking so deeply hid within many men's hearts, that they themselves scarcely feel or perceive it.
But this fear ought to be removed far from us. For we must cleave steadfastly by faith to the true and living God, and in all kind of adversity reason on this fashion:
Although men of great power be mine enemies; although this or that peril press me very sore; although I see nothing before mine eyes but present death or danger; yet will I not despair, yet will I not mistrust God, yet will I not hurt my soul with sin. For I am sure that this creature, which so sorely persecutes, vexes, or troubles me, is no god, but is under the hand and power of the true living God.
I know that one hair of my head cannot be taken away from me, without the will of him who is only and alone the true living God. Him will I fear more than the mighty power of any man, more than the crafty imaginations of mine enemies, yea, more than any creature in heaven or on earth.
And when this question shall be demanded of you, How do you understand the first commandment? then shall ye answer thus: In this precept we are commanded to fear God with all out heart, and to put our whole trust and confidence in him.