It's all about gratitude

Thus, for Seneca, the essence of a benefaction is not its content, the favor or gift contributed by one party to another, but the goodwill in which it is given: as a Stoic, his primary focus is on the animus, not the res (2.34—35; 6.2.1). What matters about a benefaction is not what is given or how much it is worth (which may be determined by fortune, good or bad), but how it is given (15.3); it is at this, the deepest, level that human relationships are most powerfully formed. At the same time, and for the same reasons, what matters about the return is not the thing reciprocated but the grateful attitude of the beneficiary: since Stoics refer all things to the animus (2.31.1), what a benefit aims to achieve is not an external counter-gift but an internal virtue, gratitude.—J. M. G. Barclay, Paul and the Gift, 48