"The eyes of the Lord are ten thousand times brighter than the sun." (Sirach 23:19)
Do not be jealous of your wife's beauty, and do not give free rein to the desires of your heart. Do not go near a strange woman, or you may fall into her snares. Do not dally with a singer in case you are trapped by her tricks. Do not gaze at a virgin, so that you do not stumble and incur penalties for her. Do not give yourself to harlots, or you may lose your inheritance. Do not look around in the streets of a city, or wander about in its deserted sections. Avert your eye from a shapely woman, and do not gaze at beauty belonging to another. Many have been seduced by a woman's beauty, and by it passion is kindled like a fire.
The Catechism identifies the counsel of guarded eyes and disciplined desire as the interior dimension of chastity - the custody of the senses that protects the integrity of the heart (CCC 2521).
Brothers and sisters, the eyes of the Lord are ten thousand times brighter than the sun. The person who sins in the belief that no one sees has misunderstood the nature of divine omniscience. God does not see less in the dark; he sees more than sunlight reveals. Behave in the dark as you would in the clearest light. And guard the eyes, because what the eyes dwell on shapes the heart.
Lord God, your eyes are ten thousand times brighter than the sun. Deliver us from the delusion that darkness hides us, and give us the custody of the eyes that guards the heart. Through Christ our Lord. Amen.