Cicero-From this impulse is developed the sense of mutual attraction which unites human beings as such; this also is bestowed by nature. The mere fact of their common humanity requires that one man should feel another man to be akin to him. For just as some of the parts of the body, such as the eyes and the ears, are created as it were for their own sakes, while others like the legs or the hands also subserve the utility of the rest of the members, so some very large animals are born for themselves alone. (De Finibus, Rackam trans. p 283).
Saint Paul- Now the body is not a single part but many. If a foot should say, "Because I am not a hand I do not belong to the body," it does not for this reason belong any less to the body. Or if an ear should say, "Because I am not an eye I do not belong to the body, " it does not for this reason belong any less to the body. If the whole body were an eye, where would the hearing be? If the whole body were hearing, where would the sense of smell be? But as it is, God placed the parts, each one of them in the body as he intended. (1 COR 14-18).