consubstantial

Thou that gavest names unto the four rivers: to the first Phison, because of the faith (pistis) which thou didst appear in the world to preach; to the second Geon, for that man was made of earth (ge); to the third Tigris, because by thee was revealed unto us the consubstantial Trinity in the heavens; to the fourth Euphrates, because by thy presence in the world thou madest every soul to rejoice (euphranai) through the word of immortality.