Now, should any one say, "And wherefore did Christ fulfill the devils' request, suffering them to depart into the herd of swine?" this would be our reply, that He did so, not as yielding to them, but as providing for many objects thereby.
-St. John Chrysostom, Homily 28 on Matthew 8, 4th Century


One, to teach them that are delivered from those wicked tyrants, how great the malice of their insidious enemies: another, that all might learn, how not even against swine are they bold, except He allow them; a third, that they would have treated those men more grievously than the swine, unless even in their calamity they had enjoyed much of God's providential care. For that they hate us more than the brutes is surely evident to every man.
-St. John Chrysostom, Homily 28 on Matthew 8, 4th Century


Through the toil of prayer and the anguish of your heart commune with those who are grieved at heart, and the Source of mercy will be opened up to your petitions.
-St. Isaac of Syria, Unknown, 7th century


But the head of every good endeavor and the guiding force of right actions is perseverance in prayer. By means of it we can daily obtain the rest of the virtues by asking God for them. By this means are engendered in those deemed worthy the fellowship of God’s holiness and of spiritual energy and the attachment of the mind disposed toward the Lord in ineffable love. For the person who daily forces himself to persevere in prayer is enflamed with divine passion and fiery desire from a spiritual love toward God, and he receives the grace of the sanctifying perfection of the Spirit.
-St. Makarios the Great, Homilies 40.2, in Spiritual Homilies, 4th century