That the Love of a Human Being, However Constant in Loving and Returning Love, Perishes; While He Who Loves God Never Loses a Friend
14 This is it that is loved in friends; and so loved that a man's conscience accuses itself if he love not him by whom he is beloved, or love not again him that loves him, expecting nothing from him but indications of his love. Hence that mourning if one die, and gloom of sorrow, that steeping of the heart in tears, all sweetness turned into bitterness, and upon the loss of the life of the dying, the death of the living. Blessed be he who loves You, and his friend in You, and his enemy for Your sake. For he alone loses none dear to him to whom all are dear in Him who cannot be lost. And who is this but our God, the God that created heaven and earth, and fills them, because by filling them He created them? None loses You but he who leaves You. And he who leaves You, whither goes he, or whither flees he, but from You well pleased to You angry? For where does not he find Your law in his own punishment? “And Your law is the truth,” and truth Thou.
Source: Confessions (New Advent)