You shall have no other gods.
I found this helpful note during my devotions this morning. It’s from “Concordia the Lutheran Confessions: a Reader’s Edition of the Book of Concord” second edition, Concordia Publishing House, 2006.
“Luther spends more time on the First Commandment than on any other portion of the Catechism, explaining how essential it is to know, trust, and believe in the true God and to let nothing take His place. He was convinced that where this commandment was being kept, all other commandments would follow. A right relationship with God produces right relationships with fellow human beings.”