How little is this really felt! How many things are done continually, which men would never do if they thought they were seen! How many matters are transacted in the rooms of imagination, which would never bear the light of day! Yes; men entertain thoughts in private, and say words in private, and do acts in private, which they would be ashamed and blush to have exposed before the world. The sound of a footstep coming has stopped many a deed of wickedness. A knock at the door has caused many an evil work to be hastily suspended, and hurriedly laid aside. But oh, what miserable folly is all this! There is an all-seeing Witness with us wherever we go. Lock the door, pull down the blind, turn out the light; it doesn’t matter, it makes no difference; God is everywhere, you cannot shut Him out, or prevent His seeing.
—J. C. Ryle
Thoughts for Young Men, 83.