5 For in this body of ours there is a struggle; as long as we live, we are in combat; as long as we are in combat, we are in peril; but, “in all these things we are conquerors through Him who loved us.” Our combat ye heard of just now when the Apostle was being read. “All the law,” says he, “is fulfilled in one word, even in this, You shall love your neighbour as yourself.” This love is from the Holy Spirit. “You shall love your neighbour as yourself.” First see, if you know yet how to love yourself; and then will I commit to you the neighbour whom you are to love as yourself.
But if you do not yet know how to love yourself; I fear lest you should deceive your neighbour as yourself. For if you love iniquity, you do not love yourself. The Psalm is witness; “But whoso loves iniquity, hates his own soul.” Now if you hate your own soul, what does it profit you that you love your flesh? If you hate your own soul and love your flesh, your flesh shall rise again; but only that your soul may be tormented. Therefore the soul must first be loved, which is to be subdued unto God, that this service may maintain its due order, the soul to God, the flesh to the soul. Would you that your flesh should serve your soul? Let your soul serve God. You ought to be ruled, that you may be able to rule. For so perilous is this struggle, that if your Ruler forsakes you, ruin must ensue.
Source: Sermons on Selected Lessons of the New Testament (New Advent)