Watch your heart during all your life

Watch your heart during all your life—examine it, listen to it, and see what prevents its union with the most blessed Lord. Let this be for you the science of all sciences, and with God’s help you will easily observe what estranges you from God, and what draws you towards Him and unites you to Him. It is the evil spirit more than anything else that stands between our hearts and God; he estranges God from us by various passions, or by the desires of the flesh, by the desires of the eyes, and by worldly pride.

from the book: My Life in Christ, Saint John of Kronstadt