The first commandment reads, "You shall have no other gods."
But what does it mean to "have a god"?
Luther writes in the Large Catechism, "Many a person thinks that he has God and everything in abundance when he has money and possessions. He trusts in them and boasts about them. Such a person has a god by the name of 'Mammon'." He also writes, "So too, whoever trusts and boasts that he has great skill, prudence, power, favor, friendship, and honor also has a god. But it is not the true and only God."
"Having a god" means to have something in which the heart trusts entirely. Everyone has a god. But not everyone has the true and only God.
Which 'gods' do you have? What things do you rely upon? What things do you think about to make yourself feel secure?
God forbids us from trusting in things other than Him. But He doesn't do this to harm us, but to protect us from relying upon things that are temporary. Should we 'have gods' that will not protect and defend us in the end, how could a loving God allow us to trust in them without warning us?
God commands us to hold Him alone as god. For our safety. For our good. And because He loves us. He is the only One who has created, and He is the only One who saves. Trust in the Lord, for He alone is faithful as His holy death and resurrection prove.