"This is the hardest of all: to close the open hand out of love, and keep modest as a giver"

This quote suggests that it is tough to give without expecting anything in return and to do so without looking for acknowledgment or appreciation. Nietzsche recommends that real generosity comes from a location of selflessness which offering should not be provided for individual gain or to boost one's ego. To close the open hand out of love suggests to provide without expecting anything in return and to maintain a sense of humbleness and modesty as a giver.