The person who understands the evil in his own heart is the only person who is useful, fruitful, and solid in his beliefs and obedience. Others only delude themselves and thus upset families, churches, and all other relationships. In their self-pride and judgment of others, they show great inconsistency.

Your state is not at all to be measured by the opposition that sin makes to you, but by the opposition you make to it.

Mortification from a self-strength, carried on by ways of self-invention, unto the end of a self-righteousness, is the soul and substance of all false religion in the world.

A man may be carried on in a constant course of mortification all his days; and yet perhaps never enjoy a good day of peace and consolation.

Spiritual wisdom consists in finding out the subtleties, policies, and depths of any indwelling sin... to trace this serpent in all its turnings and windings; be able to say, at its most secret actings, 'This is your old way and course; I know what you aim at.'

The root of an unmortified course is the digestion of sin without bitterness in the heart.

Be killing sin or it will be killing you.