The Large Catechism The Ten Commandments The First Commandment.
Thou shalt have no other gods before Me. 1] That is: Thou shalt
have [and worship] Me alone as thy God. What is the force of
this, and how is it to be understood? What does it mean to have
a god? or, what is God? 2] Answer: A god means that from which
we are to expect all good and to which we are to take refuge in
all distress, so that to have a God is nothing else than to
trust and believe Him from the [whole] heart; as I have often
said that the confidence and faith of the heart alone make both
God and an idol. 3] If your faith and trust be right, then is
your god also true; and, on the other hand, if your trust be
false and wrong, then you have not the true God; for these two
belong together, faith and God. That now, I say, upon which you
set your heart and put your trust is properly your god. 4]
Therefore it is the intent of this commandment to require true
faith and trust of the heart which settles upon the only true
God, and clings to Him a