Serenus: If we had this knowledge, or rather faith, of which I treated above; viz., to believe that all things were brought about by God, and ordered for the good of our souls, we should not only never despise them, but rather pray without ceasing for them as our own members, and sympathize with them with all our hearts and the fullest affection (for “when one member suffers, all the members suffer with it” 1499 ), as we know that we cannot possibly be perfected without them inasmuch as they are members of us, just as we read that our predecessors could not attain the fulness of promise without us, as the Apostle speaks of them as follows: “And these all being approved by the testimony of faith, received not the promise, God providing some better thing for us that they should not be perfected without us.” 1500 But we never remember that holy communion was forbidden them; nay rather if it were possible, they thought that it ought to be given to them daily; nor indeed according to the words of the gospel which you incongruously apply in this sense “Give not that which is holy to dogs,” 1501 ought we to believe that holy communion becomes food for the demon, and not a purification and safeguard of body and soul; for when it is received by a man it, so to speak, burns out and puts to flight the spirit which has its seat in his members or is trying to lurk in them. For in this way we have lately seen Abbot Andronicus and many others cured. For the enemy will more and more abuse the man who is possessed, if he sees him cut off from the heavenly medicine, and will tempt him more often and more fearfully, as he sees him removed the further from this spiritual remedy. 1502
S. Matt. vii. 6.373:1502
The question whether the Holy Communion should ever be given to those possessed is discussed by S. Thomas Aquinas, in the Summa III. Q. lxxx. Art. 9, and answered in the affirmative, the authorities quoted in its favour being this passage from Cassian, and the third Canon of the 1st Council of Orange (a.d. 441).