cast (one's) bread upon the waters
Do good deeds without being motivated by a potential reward. Maia left her high-powered accounting job to cast her bread upon the waters and care for her mother.
Cast one's bread upon the waters.
Prov. Act generous because you feel it is right and not because you expect a reward. (Biblical.) Joseph is casting his bread upon the waters, supporting Bob while he works on his novel Cast your bread upon the waters; make a generous contribution to our cause.