Catena Aurea on Luke 10:29–37: Augustine of Hippo

Hereby we understand that he is our neighbour, to whomsoever we must shew the duty of compassion, if he need it, or would have shewn if he had needed it. From which it follows, that even he who must in his turn shew us this duty, is our neighbour. For the name of neighbour has relation to something else, nor can any one be a neighbour, save to a neighbour; but that no one is excluded to whom the office of mercy is to be denied, is plain to all; as our Lord says, Do good to them that hate you. (Matt. 5:44.) Hence it is clear, that in this command by which we are bid to love our neighbour, the holy angels are included, by whom such great offices of mercy are bestowed upon us. Therefore our Lord Himself wished also to be called our neighbour, representing Himself to have assisted the half dead man who lay in the way.