This is a very insightful quote by Jonathan Edwards:
I have had a vastly greater sense of my own wickedness, and the badness of my heart, than ever I had before my conversion. It has often appeared to me, that if God should mark iniquity against me, I should appear the very worst of all mankind, of all that have been, since the beginning of the world to this time, and that I should have by far the lowest place in hell. When others that have come to talk with me about their soul-concerns have expressed the sense they have had of their own wickedness, by saying that it seemed to them that they were as bad as the devil himself, I thought their expressions seemed exceeding faint and feeble, to represent my wickedness.
My wickedness, as I am in myself, has long appeared to me perfectly ineffable, and swallowing up all thought and imagination, like an infinite deluge or mountains over my head. I know not how to express better what my sins appear to me to be, than by heaping infinite upon infinite, and multiplying infinite by infinite. Very often, for these many years, these expressions are in my mind and in my mouth, ‘Infinite upon infinite—infinite upon infinite!’ When I look into my heart and take a view of my wickedness, it looks like an abyss, infinitely deeper than hell. And it appears to me that, were it not for free grace, exalted and raised up to the infinite height of all the fullness and glory of the great Jehovah, and the arm of his power, and grace stretched forth in all the majesty of his power, and in all the glory of his sovereignty, I should appear sunk down in my sins below hell itself; far beyond the sight of everything but the eye of sovereign grace, that can pierce even down to such a depth. And yet it seems to me that my conviction of sin is exceedingly small and faint; it is enough to amaze me that I have no more sense of my sin. I know, certainly, that I have very little sense of my sinfulness. When I have had turns of weeping and crying for my sins, I thought I knew at the time that my repentance was nothing to my sin.
Dr. Steven R. Cook