Thomas Aquinas,
Summa Theologiae — Question 26 - OF THE ORDER OF CHARITY…
“ Art. 12 - Whether a man ought to love more his benefactor than one he has benefited? Objection 1: It would seem that a man ought to love his benefactor more than one he has benefited. For Augustine says (De Catech. Rud. iv) : "Nothing will incite another more to love you than that you love him first: for he must have a hard heart indeed, who not only refuses to love, but declines to return love already given." Now a man's benefactor forestalls him in the kindly deeds of charity. Therefore we ought to love our benefactors above all. ”
