I. “You Shall Worship the Lord Your God and Him Only Shall You Serve”

From The Catechism of the Catholic Church

2088
The first commandment requires us to nourish and protect our faith with
prudence and vigilance, and to reject everything that is opposed to it. There
are various ways of sinning against faith:
Voluntary doubt about the faith disregards or refuses to hold as true what God
has revealed and the Church proposes for belief. Involuntary doubt refers to
hesitation in believing, difficulty in overcoming objections connected with the
faith, or also anxiety aroused by its obscurity. If deliberately cultivated
doubt can lead to spiritual blindness.

PART THREE: LIFE IN CHRIST

SECTION TWO THE TEN COMMANDMENTS
- CHAPTER ONE YOU SHALL LOVE THE LORD YOUR GOD WITH ALL YOUR HEART, AND WITH ALL YOUR SOUL, AND WITH ALL YOUR MIND
  - Article 1 THE FIRST COMMANDMENT
    - I. “You Shall Worship the Lord Your God and Him Only Shall You Serve”

From The Catechism of the Catholic Church – rosary.team