Enneads III.5: Of Love, or "Eros."
Love Is a Gadfly
Love, therefore, is similar to a gad-fly; needy by nature, it still remains needy, whatever it may obtain; it could never be satisfied, for this would be impossible for a being that is a mixture; no being could ever be fully satisfied if by its nature it be incapable of attaining fulness; even were it satisfied for a moment, it could not retain anything if its nature made it continue to desire. Consequently, on one side, Love is deprived of all resources because of its neediness; and on the other, it possesses the faculty of acquisition, because of the reason that enters into its constitution.