The 1st Commandment

Westminster Shorter Catechism
Q. 45. What is the first commandment? The first commandment is: You shall have no other gods before me.
Q. 46. What does the first commandment require? The first commandment
requires us to know and recognize God as the only true God and our God, and to worship and glorify him accordingly.
Q. 47. What does the first commandment forbid? The first commandment forbids denying God or not worshiping and glorifying him as the true God and our God. It also forbids giving worship and glory, which he alone deserves, to anyone or anything else.
Q. 48. What are we specifically taught in the first commandment by the words before me? The words before me in the first commandment teach us that God, who sees everything, notices and is very offended by the sin of having any other god.