Be hungry for God and nothing else. Find good in things not for their own sake, but because they express the goodness of God.
To reach satisfaction in all desire its possession in nothing.
To come to possess all desire the possession of nothing.
To arrive at being all desire to be nothing.
To come to the knowledge of all desire the knowledge of nothing.
To come to the pleasure you have not you must go by a way in which you enjoy not.
To come to the knowledge you have not you must go by a way in which you know not.
To come to the possession you have not you must go by a way in which you possess not.
To come to be that which you are not you must go by a way in which you are not.
When you turn toward something you cease to cast yourself upon the all.
For to go from all to the all you must deny yourself of all in all.
And when you come to the possession of the all you must possess it without wanting anything.
Because if you desire to have something in all your treasure in God is not purely your all.
~ John of the Cross
Whoever finds his life will lose it, and whoever loses his life for my sake will find it. (Matthew 10:39, ESV)