[86a bottom] R’ Pappa: Debt repayment is a Mitzvah.
R’ Shechter: For any positive commandment that the Torah specifies a reward, we do not punish someone for missing out on it (because the punishment is the lack of the reward itself). However, Tzedakah (“charity”) is an exception to this rule.
Radvaz: The “extra” money we get is not ours and we are simply tasked with being the agents to ‘hand-out’ G-d’s payments. This money is literally “owed” to others [see previous lessons RoshHashana#6 & Sukkah#55 for more].
D-E-ep Thoughts: It becomes so much easier to part with what we have when we recognize Hashem as the owner of all. We should always be thankful for every ‘little’ thing that we have graciously been blessed with. We should try to emulate G-d in all His ways and specifically to become Kosher Contributors (especially, when it might be very tough to).