"You shall love the Lord your God with all your heart, and with all your soul and with all your strength" (Deut 6:5).
The first commandment summons man to believe in God, to hope in him, and to love him above all else.
"You shall worship the Lord your God" (Mt 4:10). Adoring God, praying to him, offering him the worship that belongs to him, fulfilling the promises and vows made to him are acts of the virtue of religion which fall under obedience to the first commandment.
The duty to offer God authentic worship concerns man both as an individual and as a social being.
"Men of the present day want to profess their religion freely in private and in public" (DH 15).
Superstition is a departure from the worship that we give to the true God. It is manifested in idolatry, as well as in various forms of divination and magic.
Tempting God in words or deeds, sacrilege, and simony are sins of irreligion forbidden by the first commandment.
Since it rejects or denies the existence of God, atheism is a sin against the first commandment.
The veneration of sacred images is based on the mystery of the Incarnation of the Word of God. It is not contrary to the first commandment. You shall not take the name of the Lord your God in vain.72 You have heard that it was said to the men of old, "You shall not swear falsely. . But I say to you, Do not swear at all.73