The Holy Spirit is the third person of the Holy Trinity.
The Holy Spirit is an eternal person who was present before creation.
Nature and Procession
The Holy Spirit proceeds eternally from the Father before creation. This concept of the Holy Spirit proceeding solely from the Father is a central tenet in Orthodox theology and is referred to as the monarchy of the Father.
The Father is considered the sole origin (archē, or ἀρχή in Greek) from whom the Son is begotten and the Holy Spirit proceeds.
The divinity of the Holy Spirit has been affirmed since at least the First Council of Constantinople in 381. Heresies that deny the divinity of the Holy Spirit, such as those of the Pneumatomachians (also known as Macedonians), have been historically opposed in the East.
The Cappadocian Fathers, including Saint Basil the Great, Saint Gregory the Theologian, and Saint Gregory of Nyssa, were explicit in discussing the divinity and the distinct personhood - Hypostasis - of the eternal person of the Holy Spirit.
In Orthodox theology, it is understood that humanity engages with the energies of God, which are natural to God's essence. Claims are not made about God's essence, other than the revelation that there are three persons in one essence.
The Filioque Controversy
A significant point of theological divergence arose with the addition of the Filioque clause ("and the Son") to the Nicene Creed in the West. While the Orthodox position is that the Holy Spirit proceeds from the Father through the Son, the Western addition states that the Holy Spirit proceeds from the Father and the Son.
Role and Activity
The Holy Spirit is often referred to by the Greek term Paraclete, meaning councellor, helper, or advocate, as described by Jesus Christ in the New Testament. The Holy Spirit is what guides Christians towards Truth.
The Holy Spirit is essential for the journey of Theosis, which is the process of journeying back towards God. Through the Holy Spirit, individuals come back to Christ and follow Christ on this journey.
The Holy Spirit leads and inspires The Church founded by Jesus Christ and directed and led by the Apostles. While the Holy Spirit can work on people outside the Orthodox Church, perhaps leading them towards it, this is seen as the Holy Spirit working "on the outside".
The fullness of the Spirit is understood to be received inside a person once they receive Baptism. This is the point at which Orthodox Christians receive the Holy Spirit inside them. This indwelling is seen as a unique aspect of being an Orthodox Christian, allowing the Holy Spirit to work internally.
The body is considered the temple of the Holy Spirit. The concept of the incorruptible bodies of saints is seen as an indication of a person being filled with the Spirit. Hence cremation is a desecration of the body because it is the dwelling place of the Holy Spirit.
Through the indwelling and power of the Holy Spirit, individuals are brought into the mysteries of the church. Mystagogy is the process of being led into these mysteries. The mysteries are understood to be super-rational, meaning they are beyond human rational faculties but not irrational.
The Holy Spirit is seen as active in the new creation since the Incarnation, beginning with the impregnation of the Theotokos. The Incarnation marks a new creation and redemption. Pentecost is understood as an anticipation of the last days, when history culminates in universal communion in God.
In Orthodox worship, the Holy Spirit is invoked at the beginning of worship and is asked to sanctify the gifts during the Sacraments in a petition called the Epiclesis. The Holy Spirit is the main agent in humanity's restoration through communion in Christ.
The Christian life is described as being about the collection of the Holy Spirit, aiming to acquire more of the Spirit's indwelling to be fully inspired by God.
Identifying the Spirit's Presence
The presence of the Holy Spirit is known by its fruits. These fruits include attributes such as:
Joy, Love, Peace, Patience, Kindness, Goodness, Faithfulness, Gentleness, Self-control, and Spiritual gifts
According to tradition, irrationality, emotionalism, and hyperactivity are not considered indicative of the fruits of the Holy Spirit, and sometimes can be attributed to demonic activity.
Blasphemy against the Holy Spirit is considered an unforgivable sin, understood as attributing the works performed by the Holy Spirit to Satan.
One is encouraged to look at the lives of the saints to see the Holy Spirit at work, as they are seen as people who were filled with the Spirit.
Symbolism
In iconography and scripture, the Holy Spirit is often depicted as a dove. The dove symbol appears in the account of Noah and The Flood, and prominently in the description of the descent of the Holy Spirit during Christ's baptism. These instances symbolise the fulfilment of God's promise.