Praeparatio Evangelica (The Preparation of the Gospel)

[PORPHYRY] 'To the God who is over all, as a certain wise man said, we must neither offer by fire nor dedicate any of the things of sense; for there is no material thing which is not at once impure to the immaterial. Wherefore neither is speech by the outward voice proper to Him, nor even the inward speech, whenever it is defiled by passion of the soul. But we worship Him in pure silence, and with pure thoughts concerning Him. United therefore and made like to Him, we must offer our own self-discipline as a holy sacrifice to God, the same being both a hymn of praise to Him and salvation to us. Therefore this sacrifice is perfected in passionless serenity of soul and in contemplation of God.'