Or HaChaim on Exodus 22:24/אור החיים על שמות כ״ב:כ״ד

1 אם כסף תלוה, If you lend money, etc. Rabbi Yishmael says in the Mechilta that the word אם in any other verse in the Torah means that something is optional. In this case the word אם means "when" and not "if." We need to understand the whole concept of G'd employing the word אם to describe things which may or may not occur. Why does G'd not phrase legislation in a definitive manner? Perhaps the Torah wants to provide an answer also to those who ask why some people seem to enjoy far more riches than they can possibly need in their lives. Such a questioner may well point to our patriarch Jacob (Genesis 28,20) who asked G'd for the necessities of life, i.e. bread to eat, and clothes to wear." While we can understand that depriving man of his necessities may have morally rewarding results seeing that the person so deprived may be punished for wrongdoing and may turn to prayer in order to expiate his guilt, what is the educational value of giving someone excess wealth? Our verse provides the answer to this question. Generally speaking, G'd in His great kindness provides generously for the needs of all His creatures. He allocates a fixed amount for these needs. When a person has not qualified for receiving his needs at the hands of G'd directly because he is guilty of sinful conduct, G'd does not recall the amount that would have been allocated to such a person, but He redirects it to someone else. As a result, the person who does not receive his livelihood from G'd directly, either suffers deprivation or is forced to receive his livelihood through another channel. Receiving one's livelihood by means of a fellow human being instead of at the hands of G'd is demeaning for the recipient. When G'd re-allocates the channels by which such a sinful person receives his livelihood, He practices two virtues. 1) By punishing the person in question in this world for his sins, the sinner is encouraged to rehabilitate himself. 2) G'd gives the wealthy person an opportunity to use his wealth constructively by performing charitable deeds.

2This is the true meaning of: "when you lend money to My people, the poor who is with you." The Torah suggests that if we find ourselves in possession of more than we need, we are to lend it to someone whom the Torah, i.e. G'd, describes as עמי, "My people." The meaning of this verse is that if you become aware that you have more money than you need for your personal requirements it is clear that the excess had originally belonged to someone else, i.e. "the poor amongst you." This is a clear hint that you should open your hand to lend to the poor part of what used to be his, or had been intended for him. Perhaps the Torah even hinted to the wealthy person that when he extends a loan to the poor he should not credit himself with being a superior person seeing that the loan only represents a partial return to the poor of what had originally been intended for him by G'd Himself. This may also be the reason why the Torah says: "do not act as if you were his creditor." The word נשה is related to נשיאות, a superior status or posture; the Torah reminds the lender that what he lends to the poor was the property of the poor in the first place. This is why the Torah goes on to speak about the prohibition to charge interest on the loan.