Philo Judaeus De Virtutibus 83

[83] And he enjoins his subjects not to hang back on that account, and to be more slow to contribute to the necessities of others, but rather with open hands and willing minds very cheerfully to give to those who have need, considering that gratitude may in some degree be looked upon as interest repaid at a more favourable season for what was lent in an hour of necessity, being repaid by the voluntary inclination of the receiver of the kindness. And if a person be not willing wholly to give, still at all events let him lend, so as to give the temporary use of what is wanted freely and cheerfully, without expecting to receive anything beyond the principal.