Now every one, as a matter of fact, loves his own life, but some love it absolutely, without qualification, and others love it partially, in a qualified way. To love someone is to will good to that person; so, to love one's own life is to will good to it. Therefore one who wills what is good without qualification to his own life, loves it unqualifiedly; while one who wills his life some partial good loves it in a qualified way. Now the unqualified goods of life are those which make a life good, namely, the highest good, which is God. Thus, one who wills the divine and spiritual good to his life, loves it unqualifiedly; while one who wills it earthly goods, such as riches, honors and pleasures, and things of that sort, loves it in a qualified way.
[St. Thomas Aquinas, Commentary on the Gospel of John, Chapters 6-12, Larcher & Weisheipl, trs., Catholic University of America Press (Washington, DC: 2010) p. 279.]