THE HOLY SPIRIT is the third person of the Holy Trinity, indivisible, "Within you, there is breath, and material impersonal in nature, but in God as life itself, breath is a personal spirit, indivisible, simple, that gives Life to everything." "We may ask, why is the third Person called Spirit, and why is He a separate Person, when God, even without Him, is Spirit? I answer: The Holy Spirit is called Spirit in relation to creatures: the Lord breathed with His Hypostatic Spirit, and there appeared, by the power of His Life-Giving Spirit, an innumerable host of spirits: In the power of His Spirit lies their strength; He breathed with His Spirit into man's body: and now man became a living soul, and from this Breath, until now, people are born, and will be born until the end according to the commandment: increase and multiply. If the Lord created by His Spirit so many personal separate beings, then why is it impossible for the Holy Spirit Himself to be a Person, or a personal creative Being? If there are countless numbers of created personal spirits, then is God Himself to remain without Spirit, without His independent, Hypostatic Personality?"
"The Holy Spirit, like air, 'is present everywhere and fillest [penetrates] all things.'" "The Lord Jesus Christ Himself likens the Holy Spirit in His action to the substance of water (John 7:38-39), air, or wind (John 3:8)." "As the air in the room is identical with the outer air and comes from it, and necessarily presupposes the air spread out everywhere, so in like manner, our soul, the breath of the Spirit of God, presupposes the existence of the omnipresent, transcendent Spirit of God."
"It is the Spirit that quickeneth" (John 6:63). "The life in creatures belongs to God, from the time of their creation, and to God the Son, their creator, bringing them from non-existence to existence... The Holy Spirit creates us in the womb of our mother; our spiritual wealth belongs to the Holy Spirit."
Our soul lives by the Holy Spirit, through Him we pray, through Him we become purified, through Him we save ourselves. "As breath is necessary for the body, and without breathing man cannot live, so without the Breath of the Holy Spirit the soul cannot live the true life. What the air is for the body, the Holy Spirit is for the soul. Air is likened to the Spirit of God. The Spirit breathes wherever It wishes." "He who prays by the Holy Spirit." "Prayer is the breath of the soul, as air is the breath of the natural body. We breathe by the Holy Spirit. You cannot say a single word of prayer from your heart without the Holy Spirit."
"As in a conversation with people the sound-conveying medium between our words and the words of another is air, which is everywhere and fills all space, and through air the words reach the ear of another, and without air it would be impossible to speak and hear: so in a spiritual manner, in communication with spiritual beings the mediator is the Holy Spirit, omnipresent and transcendent."
"We are filled with One Spirit: Do you see how the Holy Spirit surrounds us like water and air on all sides?"
"For a long time I did not know with full clarity how necessary was the strengthening of our soul by the Holy Spirit. And now the Most Merciful One gave me the opportunity to find out how indispensable it is. Yes, it is necessary every minute, as is breathing, necessary at prayer, and throughout life. It is necessary that our heart rest on a rock. And that rock is the Holy Spirit."
"All upright people are filled by the One Divine Spirit, similarly as a sponge is saturated with water. The comforting Holy Spirit, filling the universe, penetrates through all the believing, humble, good, and simple souls of men; living in them, reviving them and strengthening them; He becomes all for them: light, power, peace, joy, success in deeds - especially in an upright life. The Holy Spirit is all goodness."
Thus we see what the dogma of the Holy Spirit in the thought of Father John and how closely it is connected with life. The teaching about the Holy Spirit is at the same time teaching about the life of the world, about the source and nourishment of all uprightness and holiness.
St. John of Kronstadt