Roman Catechism 24.43

Chapter 24 — Part III: The Decalogue — The First Commandment

Section 43. The flesh, also, distrusting the promises of God, sometimes magnifies the power of the enemy to such an extent, as to believe itself unable to withstand his assaults; while, on the contrary, a firm and unshaken faith, which wavers not, but relies confidently on the strength and power of God, animates and confirms man. For it says: The Lord is my light and my salvation; whom shall I fear?