George A. Smith shared this often with his family. His grandson, George Albert Smith and President of the Church repeated it often,

“There is a line of demarcation well defined between the Lord’s territory and the devil’s territory. If you will stay on the Lord’s side of the line you will be under his influence and will have no desire to do wrong; but if you cross to the devil’s side of that line one inch you are in the tempter’s power and if he is successful, you will not be able to think or even reason properly because you will have lost the Spirit of the Lord.”

Teachings of Presidents of the Church: George Albert Smith, Chapter 18: Stay on the Lord’s Side of the Line