They allowed him to keep the extra money as a gesture of 'goodwill'.
a 'goodwill' ambassador on a 'goodwill' tour/mission
She has/feels 'goodwill' toward all her coworkers.
(..) Not even my own kin. Fili, don't be a fool. You belong with the company. I belong with my brother. By my beard, is that the time?! Ah! Go now with our goodwill... ...and good wishes. - And may your return bring good fortune... Wait! ...to all! Good bye. (..)2013 The Hobbit: The Desolation of Smaug