Ben Sira 23:18

18 The one who sins against his marriage bed says to himself, "Who can see me? Darkness surrounds me, the walls hide me, and no one sees me. Why should I worry? The Most High will not remember sins."

Ben Sira 23:18 In-Context

16 Two kinds of individuals multiply sins, and a third incurs wrath. Hot passion that blazes like a fire will not be quenched until it burns itself out; one who commits fornication with his near of kin will never cease until the fire burns him up.
17 To a fornicator all bread is sweet; he will never weary until he dies.
18 The one who sins against his marriage bed says to himself, "Who can see me? Darkness surrounds me, the walls hide me, and no one sees me. Why should I worry? The Most High will not remember sins."
19 His fear is confined to human eyes and he does not realize that the eyes of the Lord are ten thousand times brighter than the sun; they look upon every aspect of human behavior and see into hidden corners
20 Before the universe was created, it was known to him, and so it is since its completion.
New Revised Standard Version Bible, copyright 1989, Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.