Happiness is found within ourselves, and blessed is the man who has understood this. Happiness is a pure heart, for such a heart becomes the throne of God. Thus says Christ of those who have pure hearts: “I will visit them, and will walk in them, and I will be a God to them, and they will be my people.” (II Cor. 6:16) What can be lacking to them? Nothing, nothing at all! For they have the greatest good in their hearts: God Himself! ~ St. Nektarios of Aegina
… the human heart, along with the mind, is an organ of knowledge. And the knowledge of the heart is higher than the knowledge of the mind. ~ St. Luke of Crimea
Create in me a clean heart, O God; and renew a right spirit within me. ~ Psalm 51:10