The first duty of a Christian, of a disciple and follower of Jesus Christ, is to deny oneself. To deny oneself means to give up one's bad habits, to root out of the heart all that ties us to the world; not to cherish bad desires and thoughts; to quench and suppress bad thoughts; to avoid occasions of sin; not to do or desire anything from self-love but to do everything out of love for God. To deny oneself means, according to the Apostle Paul, to be dead to sin and the world, but alive to God.
The key to Divine gifts is given to the heart by love of neighbor, and, in proportion to the heart's freedom from the bonds of the flesh, the door of knowledge begins to open before it.
And among all the works of God, before which the mind grows faint with awe, which so rejoices yet overwhelms the soul as the Passion of our Savior? For as often as we dwell, as best we can, upon His Omnipotence, which He shares with the Father in one and the same nature, more wondrous does His lowliness seem to us than His power; and with more difficulty do we grasp His emptying Himself of the divine Majesty, than His sublime uplifting of the form of a servant.
You know that evil entered into us through the transgression of the commandments. Hence it is obvious that by keeping them, evil departs from us. But without the doing of the commandments we should not even aspire or hope for purity of soul, because at the very outset we do not walk on the path that leads us to purity of soul. Do not say that God can give us the grace of purity of soul even without our keeping the commandments.
As for uprooting your passions, begin with self-reproach and with awareness of your own weaknesses; and consider yourself to be deserving of afflictions.
Do not be surprised that when you draw near to virtue, grievous and intense tribulations come to you on all sides: for virtue is not considered virtue, if it does not involve hard work.