GOD - The Supreme, Eternal and Almighty Spirit Who created all things and rules the universe. He is infinite in all perfections. He is One in Three Persons. The Orthodox Church teaches that we have knowledge of God, only because God has shown himself to his creation. God is the Lord and has revealed himself unto us; blessed is he who comes in the name of the Lord (Ps 117:26-27). Also, God's self-revelation is found in His Son Jesus Christ, the fulfillment of the gradual and partial revelation of God in the Old Testament. Jesus is the one truly "blessed ... who comes in the name of the Lord."
Orthodox Christians worship the Father, Son, and Holy Spirit—the Holy Trinity, the one God (Matt. 28:19; II Cor. 13:14; I Peter 1:1-2; Rom. 14:17-18, 15:16, etc.). Following the Holy Scriptures and the Church Fathers, the Church believes that the Trinity is three divine persons who share one essence. There never was a time when any of the persons of the Trinity did not exist. God is beyond and before time and yet acts within time, moving and speaking within history.
God is not an impersonal essence or mere "higher power," but rather each of the divine Persons relates to mankind personally. Neither is the word God merely a name for three gods (i.e., polytheism), but rather the Orthodox faith is monotheist and yet Trinitarian. The God of the Orthodox Christian Church is the God of Abraham, Isaac and Jacob, the I AM who revealed himself to Moses in the burning bush (Ex. 3:2-14).
The Church primarily draws near to God and communes with Him in divine mystery, approaching God apophatically, that is, not laying down precise, exhaustive definitions of Who God is, being content to encounter God personally and yet realize the inadequacy of the human mind to comprehend him (John 1:18; I John 4:12; Is. 55:9).
The primary statement of what the Church believes about God is to be found in the Nicene-Constantinopolitan Creed, formulated in 325 and 381 AD at the First and Second Ecumenical Councils.