Jesus speaks in parables
Then Jesus entered a house, and again a crowd gathered, so that he and his disciples were not even able to eat. 21 When his family[a] heard about this, they went to take charge of him, for they said, “He is out of his mind.”
22 And the teachers of the law who came down from Jerusalem said, “He is possessed by Beelzebul! By the prince of demons he is driving out demons.”
23 So Jesus called them over to him and began to speak to them in parables: “How can Satan drive out Satan? 24 If a kingdom is divided against itself, that kingdom cannot stand. 25 If a house is divided against itself, that house cannot stand. 26 And if Satan opposes himself and is divided, he cannot stand; his end has come. 27 In fact, no one can enter a strong man’s house without first tying him up. Then he can plunder the strong man’s house.
The Holy Eucharist – weapon against demons
Saint John Casian, Spiritual talks, Part I, The first talk with father Serenus, Cap. XXIX, Cap. XXX, 1-2, Cap. XXXI, 1, in Church fathers and writers (1990), vol. 57, pp. 430-431
Germanus: Hoe does it happen that we see such people (tortured by demons) not only despised and hated by all, but also kept away of the Holy Eucharist according to these words of the Gospel:
Cum se face că-i vedem pe astfel de oameni (chinuiți de demoni) nu numai disprețuiți și urâți de toți, dar chiar ținuți mereu departe de Sfânta Împărtășanie, potrivit acestor cuvinte ale Evangheliei: `Do not give dogs what is sacred; do not throw your pearls to pigs. If you do, they may trample them under their feet, and turn and tear you to pieces.` if it is possible to believe about them that as you say the humiliation of this trial it is given to them for acquiring purification?
Serenus: If we have this knowledge or better said faith that everything is done with the help of God for the benefit of soul, we won`t despise them anymore and even more than this, we will pray without cease for them like for our own limbs and we will feel sorry for them from all our heart with a deep feeling (because If one part suffers, every part suffers with it) knowing that without them, who are members of our community, we can`t reach flawlessness […] I don`t remember that the Holy Eucharist would have ever been forbidden to them. Moreover it was considered that it should be given to them daily. You understood in a wrong way these words of the Gospel: `Do not give dogs what is sacred, because it must not be believed that the Holy Eucharist has the role of nourishing the man but on the contrary its purpose is to be purifying and protector of the soul and body.
This one being received by people is like a burning fire which draws away the evil spirits that entered the men and try to hide in their limbs. […] The enemy will assault even more the besieged if he sees him separated from the heavenly Doctor and will tempt him even more often and more dangerously when he sees him kept away of the spiritual medicine.
We must consider as wretched and worthy of despise those who are stained of all crimes and misdeeds without being shown any visible sign that they are possessed by the devil and especially without passing through any trial in accordance with their deeds or through a punishment for correction. Those who have a petrified and unrepenting heart do not deserve a rapid and easy healing of this time. Their punishment will go beyond this life.