“The same undefiled flesh which He accepted from the pure loins of Mary, the all-pure Theotokos, and with which He was given birth in the body, He gives to us as food.
And when we eat of it, when we eat worthily of His flesh, each one of use receives within himself the entirety of God made flesh, our Lord Jesus Christ, son of God and son of the immaculate Virgin Mary . . .
He is present in the body bodilessly, mingled with our essence and nature, and deifying us who share His body, who are become flesh of His flesh and bone of His bone . . . This is the mystery all full of holy terror which I hesitate even to write, and tremble in recounting.
Thus, while from His immaculate mother He borrowed her immaculate flesh, and gave her in return His own divinity – o strange and new exchange! – He takes no flesh from the saints, but He does make them sharers of His own deified flesh. . . .
Just as we all receive of His fullness, so do we all partake of the immaculate flesh of His all-holy Mother which He assumed, and so, just as Christ our God, true God, became her son; even so we too – O the ineffable love for mankind! – become sons of His mother, the Theotokos, and brothers of Christ Himself . . .
The Mother of God is lady and Queen and mistress and mother of all the saints. The saints are all both her servants, since she is the mother of God, and her sons, because they partake of the all-pure flesh of her Son . . .
The saints therefore are triply her kin: first in that they are related to her from the same clay and breath of life given Adam;
Secondly, that they have communion and share with her in the flesh which was taken from her;
Thirdly and last, that on account of the hallowing which has come to pass in them through her by virtue of the Spirit, each conceives in like manner to her within himself the God of all, as she bore Him in herself.
For, if indeed she gave birth to him in the body, yet she always possessed all of Him in the Spirit, and has Him now, and will ever have Him inseparable from her.
So this is the mystery of the marriages which the Father arranged for His only-begotten Son, Who with Him is co-everlasting and of equal dignity. And He invited many, and sent his servants to invite those who were called to the weddings, and they would not come.”
St Symeon the New Theologian, c. 1010 AD
First Ethical Discourse