When the exiles return to rebuild, some of the wealthier Jews are charging their neighbors interest on loans taken to purchase food. Charging interest to a fellow child of Israel is forbidden in Exodus 22:25, Leviticus 25:36-38, and Deuteronomy 23:20-21. For a devout Jew, charging interest should be a black and white issue. Instead, Nehemiah has to call these wealthier individuals to repent of their greed and understand the price everyone has paid to come back from exile (Nehemiah 5:6-8).
I have heard many argue based on passages like this that church folks should never charge interest to brothers or sisters when giving a loan. Now, I would hate to make a law that binds the consciences of people since the New Testament does not explicitly prohibit charging interest to a brother or sister. However, I do think that sound arguments exist that this would be a very natural application of many New Testament teachings (e.g., Galatians 2:10, James 2:1-13). Additionally, I think the laws God gave to the Jewish people to ensure justice with one another give great insight into how he we should relate to each other in the family of God, the church.
Personally, I am all for people in the church loaning money to one another to help in times of struggle, but I would encourage our people not to charge interest. Such generosity would at least be a dim reflection of the goodness of Christ who gave up His riches to help poor beggars like us.