More from St John, from the same treatise:
Behold, then, matter is honoured, and you dishonour it. What is more insignificant than goat's hair, or colours, and are not violet and purple and scarlet colours? And the likeness of the cherubim are the work of man's hand, and the tabernacle itself from first to last was an image. "Look," said God to Moses, "and make it according to the pattern that was shown thee in the Mount," (Ex. 25.40) and it was adored by the people of Israel in a circle. And, as to the cherubim, were they not in sight of the people? And did not the people look at the ark, and the lamps, and the table, the golden urn and the staff, and adore? It is not matter which I adore; it is the Lord of matter, becoming matter for my sake, taking up His abode in matter and working out my salvation through matter. For "the Word was made Flesh, and dwelt amongst us." (Jn. 1.14)
It is evident to all that flesh is matter, and that it is created. I reverence and honour matter, and worship that which has brought about my salvation. I  honour it, not as God, but as a channel of divine strength and grace. Was not the thrice blessed wood of the Cross matter? and the sacred and holy mountain of Calvary? Was not the holy sepulchre matter, the life-giving stone the source of our resurrection? Was not the book of the Gospels matter, and the holy table which gives us the bread of life? Are not gold and silver matter, of which crosses, and holy pictures, and chalices are made? And above all, is not the Lord's Body and Blood composed of matter? Either reject the honor and worship of all these things, or conform to ecclesiastical tradition, sanctifying the worship of images in the name of God and of God's friends, and so obeying the grace of the Divine Spirit.
If you give up images on account of the law, you should also keep the Sabbath and be circumcised, for these are severely inculcated by it. You should observe all the law, and not celebrate the Lord's Passover out of Jerusalem. But you must know that if you observe the law, Christ will profit you nothing. (Gal. 5.2) You are ordered to marry your brother's wife, and so carry on his name, (Deut. 25.5ff) and not to sing the song of the Lord in a strange land. (Ps. 137.4) Enough of this!  "Those who have been justified by the law have fallen from grace." (Gal. 5.4)