If you deny yourself and constantly renounce your own opinions, your own will, your own righteousness–or what amounts to the same thing: the knowledge, understanding, will and righteousness of fallen nature–in order to plant within you the knowledge of God, the will of God, and the righteousness of God taught us in the holy Gospel by God Himself, then fallen nature will open fire within you and declare a savage war against the Gospel and against God. Fallen spirits will come to the help of fallen nature.
Do not fall into despondency on this account. By your firmness in the struggle, show the tenacity of your purpose and the stability of your free will. When thrown down, get up. When duped and disarmed, rearm yourself afresh. When defeated, again rush to the fight. It is extremely good for you to see within yourself both your own fall and the fall of the whole of mankind.
It is essential for you to recognize and study this fall in your own experience, in your heart and mind. It is essential for you to see the infirmity of your knowledge and intellect, and the weakness of your will.