The heart of man is a great mystery; perhaps the greatest mystery of all apart from God Himself. Who can know the heart of another human being? It is difficult enough to know one’s own heart.
And yet this is the most vital objective of the Christian spiritual life. The Church Fathers tell us that to “know oneself” is a prerequisite for becoming truly human and thus, for become truly divine, united to God by grace. St. Isaac of Syria writes that to know oneself (to know one’s heart) is greater than to raise the dead. That is because the heart is the meeting place between the spiritual and material worlds. It is there that heaven meets earth, that God communes with man, and thus the place where man finds both God as He truly is and man himself as he truly is.
Again, St. Isaac of Syria writes:
“Be peaceful within yourself, and heaven and earth will be at peace with you. Be diligent to enter into the treasury that is within you, and you will see the treasury of Heaven: for these are one and the same, and with one entry you will behold them both. The ladder of the Kingdom is within you, hidden in your soul. Plunge deeply within yourself [in the deepest chamber of the heart], away from sin, and there you will find steps by which you will be able to ascend.”
It is clear, both by revelation and by observing our created nature itself that the heart is the receptor of God’s grace. By revelation the Lord Himself gives us this word, “Blessed are the pure in heart, for they shall see God” (Matt. 5:8). Again, He points to the real place of communion between God and man when He quotes from the Prophet Isaiah, ‘These people draw near to Me with their mouth, And honor Me with their lips, But their heart is far from Me” (Matt. 15:8).
But even science reveals the special and irreplaceable nature of the heart through its knowledge of human physiology. For the cardiac cells are some of the only bodily cells that never divide.
We are born with the same heart that we will die with. The cardiac cells can die and they can grow but they cannot reproduce! Adding to the mystery is the fact that the cardio-vascular system is the first to form as the embryo develops in the womb, and the heart is the first fully functional organ of the newly forming body. The heart begins pumping blood by the twenty-third day, the third week of gestation.*
The heart is this meeting place with heaven because man is made in the image of God and this Image is found in the depths or essence of his soul, in the heart – not the physical heart as such, though there is a continuity between it and the spiritual organ referred to in Church tradition as the “heart.”
Sometimes it is said that man is made in the “image of Christ.” But this is not quite accurate. We are made in the image of God, and the Image of God is Jesus Christ, the Icon of God.
Therefore Jesus Christ is in the heart and at the heart of the mystery of our being. He is literally at the Center of our existence, of who we really are. Christ was made for the heart and the heart for Christ. Because God made man in His image, Christ is the architectural design and prototype for man not man for Christ. As human beings we are really and truly icons of God. We are each a “little christ.”
Another revealed name for Jesus Christ is God’s eternal Word. He is the One who reveals God within the heart. When God speaks to us He does so through His Word. And the Word of God is heard in the heart. When Moses approached the burning bush he did not hear the voice of a bush, but the Voice of God’s Word, Jesus Christ. And he did not hear that Word as if through a loud speaker (although it is certainly within God’s power to allow us to hear Him with our physical ears) but in the depths of his heart; in the “still, small, voice” heard by the Holy Prophet Elijah on Mount Horeb (1 Kgs. 19:12).
When the Ark of the first Covenant was built according to God’s instructions, the Word of God in the physical form of stone tablets was place into it (in Hebrew the “Ten Commandments” are actually the “Ten Words.”). And it was there, at the “mercy seat,” that God spoke to Moses “face to face.”
Whenever God speaks to man He does so by His Word, Jesus Christ, with the help of His Spirit (or “Breath”). And His Word is heard and echoes in the human heart, specifically in a pure heart that is capable of hearing the pure Word of God. The unfortunately fact is that for most of us the prophecy of Isaiah too often applies:
‘Hearing you will hear and shall not understand, And seeing you will see and not perceive; For the hearts of this people have grown dull. Their ears are hard of hearing, And their eyes they have closed, Lest they should see with their eyes and hear with their ears, Lest they should understand with their hearts and turn, So that I should heal them.’
According to God’s original design, the heart of man is the true mercy seat, the place of encounter with the true God. There is simply no other organ by which God can speak with His creature and reveal His ineffable truth and love, purifying and illumining him, pouring out the Holy Spirit into his heart (Rom. 5:5).
This was made possible through the cooperation of Mary Theotokos, who by the purity of her heart became the new Ark of the New Covenant, the living Mercy Seat, receiving the Word of God into her soul and body by the overshadowing of the Holy Spirit. It should not be surprising then that Orthodox Christians experience her as a place of encounter with the Lord, both by her sanctified presence and her intercessions.
It is only because of her “Let it be,” that “the Word became flesh” so that our humanity, and the essence of our humanity, our hearts, could be purified and prepared to receive the very life of God in a perfect union of grace. As the Fathers continually remind us, “God became Man so that man might become “god” (by grace). St. Macarius the Great says that as Mary conceived Christ in her womb so should Christ be conceived in the heart of every Christian.
All of this sounds beautiful and spiritually “romantic.” However, in order for the heart to conceive the Word fully and for the nous to be illumined by grace and reside in the heart in continual prayer, the heart must be purified of the passions and evil inclinations hiding and lurking there. The heart in its fallen condition (even in the baptized) is not only the dwelling place of God’s kingdom, but of dark and unclean spaces nurtured by sinful habits and thoughts.
Grace does not typically purify and occupy the whole heart without its continual willing cooperation. This is no easy task. “The kingdom of God suffers violence, and the violent take it by force” (Matt. 11:12). As St. Macarius explains, “There are those who speak about the kingdom of God and there are those who do something about it.” Something must be done about it because the mystery of the heart also includes the mystery of the First Adam, i.e. the reality of evil.
“The heart itself is but a small vessel,” continues St. Macarius, “yet dragons are there, and there are also lions; there are poisonous beasts and all the treasures of evil. But there too is God, the angels, the life and the kingdom, the light and the apostles, the heavenly cities and the treasuries of grace—all things are there.”
Jesus confronted this reality in, among other places, the hearts of the scribes. For knowing their thoughts He asked, “Why do you think evil in your hearts” (Matt. 9:4).
As we see from the parable of the Sower and the seed (Lk. 8:4-15), the heart is the field of spiritual battle. In the heart there is not merely “good soil.” If we begin to look and explore honestly we will also find the well-trodden and wide path of sensual comforts, as well as rocks, and thorns inhibiting the growth of the seed of the Word of God.
In the heart we find the path of hard-heartedness, lack of empathy for others, pleasure-seeking, superficiality and boredom, wasting of time and inattentiveness to spiritual things. The rocky ground of the heart gives in to despair and fear during temptation and finds no will or strength to fight the evil one, nor the zeal and love to pursue God even amidst suffering. Finally, the thorny areas of the still impure heart squeeze out God’s grace by worldly concerns, to-do lists, the pursuit of riches and possessions, distractions, gossip, and various other idols of seeming importance.
These sick passions residing in the heart give birth to evil thoughts and ultimately lead to sinful actions. For a bad tree cannot bear good fruit (Matt. 7:18).
The Orthodox spiritual life relates to the mystery of the heart. The first and primary activity of spiritual life is to begin to dig into the heart to uproot and redirect the sinful passions rooted so deeply there.
The first step is to become attentive, to begin to pay attention; to become conscious of the movements of the heart and to begin to discern between what is good and evil. This is not as easy as it sounds but it is essential.
In the Life of St. Antony (born 250AD), St. Athanasius describes what it is that the great Antony began to do when he first went out into the desert. Are you ready? “He attended to himself.”
No, he did not immediately seek to know the mysteries of God or acquire some spiritual gift of wonderworking; he simply began to pay attention to himself, his thoughts, desires, inclinations, and to bring them all into submission to God through inner attentiveness and prayer. He began the work of repentance for the purification of his heart. This is nothing other than the work of hesychia, of inner stillness and spiritual warfare. Even in the Old Testament we hear this foundational spiritual teaching, “Beware [i.e. be attentive], lest a lawless word enter your heart” (Deut. 15:9).
Such activity took up twenty years of his life before he emerged from his cell a “new creation” (Gal. 6:15), free of the tyranny of passions of the flesh and soul, and with a pure and illumined heart. As such he had brought “every thought into captivity to Christ” (2 Cor. 10:5). For “those who are Christ’s have crucified the flesh with its passions and desires” (Gal. 5:24).
By the purification of the heart, grace had come to rule in his entire being so that the mystery of Christ was manifest to all. The healing of the human heart means that the whole man comes into union with God and his kingdom. As the spokes of a wheel all converge at the center, so the heart is the center of human existence, recapitulating the spiritiual condition of the entire person.
As St. Macarius describes it: “The heart governs the whole organism, and when grace occupies all the divisions of the heart, it rules over all thoughts and members….”
Let us conclude with St. Athanasius who provides us with a verbal icon of the man who has found and climbed, as St. Isaac expressed it, “the ladder of the kingdom” within the heart.
Nearly twenty years he spent in this (inner attentiveness). And when they beheld him, they were amazed to see that his body had maintained its former condition, neither fat from lack of exercise, nor emaciated from fasting and combat with demons….The state of his soul was one of purity, for it was not constricted by grief, nor relaxed by pleasure, nor affected by either laughter or dejection. Moreover, when he saw the crowd he was not annoyed any more than he was elated at being embraced by so many people. He maintained utter equilibrium, like one guided by reason and steadfast in that which accords with nature. Through him the Lord healed many of those present who suffered from bodily ailments; others he purged of demons, and to Antony he gave grace in speech.
 The Life of Antony and The Letter to Marcellinus, Trans. By Robert C. Gregg, Paulist Press, p. 42.