Nicene and Post-Nicene Fathers, Vol. II:
On Christian Doctrine: Chapter 26

Chapter 26.—The Command to Love God and Our Neighbor Includes a Command to Love Ourselves.

27.  Seeing, then, that there is no need of a command that every man should love himself and his own body,—seeing, that is, that we love ourselves, and what is beneath us but connected with us, through a law of nature which has never been violated, and which is common to us with the beasts (for even the beasts love themselves and their own bodies),—it only remained necessary to lay injunctions upon us in regard to God above us, and our neighbor beside us.  “Thou shalt love,” He says, “the Lord thy God with all thy heart, and with all thy soul, and with all thy mind; and thou shalt love thy neighbor as thyself.  On these two commandments hang all the law and the prophets.” 1738   Thus the end of the commandment is love, and that twofold, the love of God and the love of our neighbor.  Now, if you take yourself in your entirety,—that is, soul and body together,—and your neighbor in his entirety, soul and body together (for man is made up of soul and body), you will find that none of the classes of things that are to be loved is overlooked in these two commandments.  For though, when the love of God comes first, and the measure of our love for Him is prescribed in such terms that it is evident all other things are to find their centre in Him, nothing seems to be said about our love for ourselves; yet when it is said, “Thou shall love thy neighbor as thyself,” it at once becomes evident that our love for ourselves has not been overlooked.

Footnotes

Matt. 22.37-40.