[T]he union of man with God, or deification, is a legitimate aim to seek. This is due to the preexisting union between divinity and humanity in the incarnation. It is Christ, then, who has set it before us as an aim. Union here includes all the gratuitous means of grace – baptism, Holy Communion, and perpetual repentance. Union also includes struggles such as fasting, chastity, bridling of tongue and mind. It involves constant prayer as well as acts of love and humility. It certainly includes as well God’s invisible succor to those who strive to reach him.
– Matthew the Poor, Orthodox Prayer Life – The Interior Way, p.107.