The more we desire for that which is superfluous, the more we meet with difficulties; our strength and possessions are spent in unnecessary things, and are wanting when required for that which is necessary.
MaimonidesThe business conduct of the disciples of wise men is truthful and faithful.... He does not allow himself to be made a surety or a guarantor and does not accept the power of attorney.... He lends money and is gracious. He shall not take away business from his fellow man.
Maimonides