Gregory the Great — on Ezek 2:6 (Homilies on Ezekiel, Book 1, Homily 9)

“Often indeed when we complain about the life of our neighbors, we try to change our place, to choose the seclusion of a more remote life; evidently not knowing that if the spirit is lacking, the place does not help. For that same Lot of whom we speak stood holy in Sodom, yet sinned on the mountain. Moreover, that places do not fortify the mind, the first parent of the human race himself testifies, who fell even in paradise. But all these things we speak from earth are less significant. For if a place could have saved, Satan would not have fallen from heaven. Whence the Psalmist, seeing that there are temptations everywhere in this world, sought a place where he might flee, but could not find one fortified without God. For which reason he asked that God himself become his place, on account of which place he sought, saying: "Be to me a God of protection and a fortified place, that you may make me safe." Therefore neighbors must be tolerated everywhere, because one cannot become Abel whom the malice of Cain does not exercise.”