Luther's Words: Reliance on Works is Idolatry

In reality the heathen make their own fictitious notions and dreams of God an idol and rely on what is altogether nothing.  That is what all idolatry is.  For it consists not merely in erecting an image and worshiping it.  Its seat is the heart, which stupidly stares in other direction and seeks help and comfort from creatures, saints, or devils.  It does not look to God, nor does it expect Him to be so good as to help; neither does it believe that whatever good it experiences comes from God.  Besides this, there is a false worship, an extreme form of idolatry, which we have hitherto practiced and is still prevalent in the world.  All ecclesiastical orders are based on it.  This idolatry concerns only that conscience which seeks help, comfort, and salvation in its own works, presumes to wrest heaven from God, and counts how many bequests it has made, how often it has fasted celebrated Mass, etc.  On this it relies and of this it boasts, as if it were unwilling to take anything from God as a gift but desired to earn or richly merit it, just as though He were our servant and our debtor, while we are His liege lords.  What is this but turning God into an idol, yea, a pseudo god, and regarding and elevating ourselves as God?