For if we, going about on the earth which is familiar and well known to us, being encompassed with a body, when we are journeying in a strange road, know not which way to go unless we have some one to lead us; how should the soul, being rent away from the body, and having gone out from all her accustomed region, know where to walk without one to show her the way?
Homily 28 on Matthew 8, 4th Century
Some say, 'Why do they [demons] possess people?' I answer those who wish to have this explained that the reason of these things is very deep. Somewhere one of His saints addressed God by saying, 'Your judgments are a vast abyss.' As long as we bear this in mind, we will perhaps not miss the mark.
Commentary on Luke, Homily 44. (Ancient Christian Commentary on Scripture; vol 3: Luke, Intervarsity Press)
Since he [the demoniac] received the healing of his mind, Christ commanded him to depart from the tombs and the graves and to return to that spiritual home. He who had in him the grave of the mind became a temple of God.
Exposition of the Gospel of Luke. 6.53. Taken from: Ancient Christian Commentary on Scripture; vol 3: Luke, Downer's Grove: Intervarsity Press, 2003, p. 141.