It is evident that unbelief is an evil offspring of an evil heart; for the guileless and pure heart everywhere discovers God, everywhere discerns Him, and always unhesitatingly believes in His existence.
When the man of pure heart looks at the World of Nature, that is, at the sky, the earth, and the sea and at all things in them, and observes the systems constituting them, the infinite multitude of stars of heaven, the innumerable multitudes of birds and quadrupeds and every kind of animal of the earth, the variety of plants on it, the abundance of fish in the sea, he is immediately amazed and exclaims with the Prophet David: "How great are Thy works, O Lord! In wisdom Thou made them all."
Such a man, impelled by his pure heart, discovers God also in the World of Grace of the Church, from which the evil man is far removed. The man of pure heart believes in the Church, admires her spiritual system, discovers God in the Mysteria, in the heights of the theology, in the light of the Divine revelations, in the truths of the teachings, in the commandments of the Law, in the achievements of the Saints, in every good deed, in every perfect gift, and in general in the whole of the creation. Justly then did the Lord say in His Beatitudes of those possessing purity of the heart: "Blessed are the pure in heart, for they shall see God."
St. Nektarios of Aegina
http://agapienxristou.blogspot.ca/2013/06/the-pure-in-heart-perceive-god-and.html
