"There is no sin so much like the devil as this for secrecy and subtlety and appearing in a great many shapes undiscerned and unsuspected, even appearing as an angel of light. It takes occasion to arise from everything, it perverts and abuses everything, even the exercises of real grace and real humility. It is a sin that has, as it were, many lives. If you kill it, it will live still. If you suppress it in one shape, it rises in another. If you think it is all gone, it is there still. Like the coats of an onion, if you pull one form of it off, there is another underneath. We need therefore to have the greatest watch imaginable over our hearts and to cry most earnestly to the great Searcher of hearts for his help. He that trusts his own heart is a fool."
- Jonathan Edwards, Thoughts on the New England Revival
To which I say, Amen.