The apostle Paul knew it: “For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not.”
John Newton knew it: “In defiance of my best judgment and best wishes, I find something within me which cherishes and cleaves to those evils, from which I ought to start and flee, as I should if I found a toad or a serpent was put in my food or on my bed.”
A Christian today may constantly fret over the evils in the world around him, all the while doing his best to ignore that there is something inside of him, part of his very being, that is in alliance with the external powers of evil. We may try to flee from the external evils, but wherever we flee to, the internal evil is still with us.
It is altogether vain to seek within ourselves the strength to overcome this evil. That strength cannot be found within, we must look beyond ourselves to find that power.
Paul knew where to find it: “There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit.” and ” But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead shall also quicken your mortal bodies by his Spirit that dwelleth in you.”
So did John Newton: “But though my disease is grievous, it is not desperate; I have a gracious and infallible Physician. I shall not die, but live, and declare the works of the Lord.”