Sefer HaChinuch, Mitzvah 66

The mitzvah is to lend money to the poor, as much as you are capable according to the need in order that this person will be relieved and to ease their sighing. This mitzvah of lending is stronger and more obligatory than the mitzvah to give charity. [Those] whose needs are revealed and known among (other) people and who have opened themselves to request from [others] does not have as much pressure and darkness as one who has not yet come to that (level of) embarassment and is afraid to enter it. If this person [receives] a little help via a loan, perhaps that little which is earned may be sufficient to forever obviate the need for begging. When God mercifully grants [this person] a little 'extra,' he/she will pay the debt and live on what is left over. Therefore our complete Torah advises us to support the destitute with a loan before the need to beg [arises]. The root of this mitzvah is that God desired that God's creatures be accustomed to and trained in the characteristic of kindness and mercy for it is a praiseworthy characteristic. And out of the preparedness of their bodies in the positive characteristics they will be worthy of receiving good, as we have said that goodness and blessing fall exclusively on the good. And when the Blessed One benefits those who are good, God's desire -to benefit the world- is perfected... [translation by AJWS]