When Satan cannot get a great sin in he will let a little one in, like the thief who goes and finds shutters all coated with iron and bolted inside. At last he sees a little window in a chamber. He cannot get in, so he puts a little boy in, that he may go round and open the back door. So the devil has always his little sins to carry about with him to go and open back doors for him, and we let one in and say, 'O, it is only a little one.' Yes, but how that little one becomes the ruin of the entire man!
Charles Spurgeon