The cure!

Spurgeon, "The Great Physician and His Patients"

Man cannot cure himself of sin.

He may reform, he may drive the disease
inward, and prevent its coming out upon
the skin; He may so model, and guide, and
restrain himself, that the coarser forms of
sin which are condemned among men may
not appear in him.

But the virus, the essential poison of sin,
no man can ever extract from his own
heart, nor can another man do it for him.

Jehovah Rophi, the healing Lord,
must manifest his omnipotent power.

The utmost religiousness, the most devout
prayers, the greatest possible prudence in
living, will not avail to remove the taint of sin,
if they spring from an unrenewed heart.

The carnal mind is enmity against God, and is not
reconciled to God, neither, indeed, can it be.