If anyone is poor among your fellow Israelites in any of the towns of the land the LORD your God is giving you, do not be hardhearted or tightfisted toward them. Rather, be openhanded and freely lend them whatever they need. Be careful not to harbor this wicked thought: “The seventh year, the year for canceling debts, is near,” so that you do not show ill will toward the needy among your fellow Israelites and give them nothing. They may then appeal to the LORD against you, and you will be found guilty of sin.- (Deuteronomy 15:7-9)
One of the really interesting things about trying to shape your life around following God is the way that we receive teaching about what God wants. A lot of what we learn about God's will comes from the things that we read in scripture. For whatever reason, God has chosen to use this method to give us our clearest teaching about himself. However something funny happens in this process because the things that are written in scripture are bound to their time and their place in many ways. This passage from Deuteronomy is talking about how the Israelites should conduct themselves in the country which God will establish them in and watch over them in.
One trap which you might fall in to is to read this passage and then think "I should behave in exactly the way that is outlined in this passage". This is a problem because there are things assumed in these passages which are not true for us today. We do not live in Israel. We do not have a national Sabbath day. We do not have an understanding that God expects this kind of seven year cycle of the forgiveness of debts. So we have to go back and look at this passage and think how can we apply what we learn from this passage to our modern pluralistic country with its capitalist economy and its democratic politics.
This passage deals with the needy in Israel. What they are instructed to do here is to be generous with those who are in need in the land and lend to others if they have needs. In this context lending means giving money or things with the expectation of repayment. That's why there's the qualifier about not being wicked and thinking "the year of the jubilee when I have to forgive all my debts is soon so therefore I won't give". What God expects is that the people will loan money to people when they are in need, that there will be a period for them to try and repay the debt, but at the end of the seven year cycle the debt is forgiven and the person can move on.
If we try and abstract this a little more or make it more general than it is here, what we see is God making a commandment to the people to give resources to those who need it and give them a chance to repay what they are given. However, if they can't repay it by the seven year deadline then you simply forgive what is owed and move on. Ultimately debt is a form of idolatry and if people become trapped or enslaved in perpetuity to someone because they had a need, they are no longer free to belong only to God.
If we try and apply this in modern terms I think we can say this. When we see someone around us who is in need, we should try and help them by lending them what they need freely. This offers them a chance to repay us and feel a sense of dignity and control over what is going on in life. However, these kinds of debts shouldn't be held in perpetuitiy. If it seems someone will not be able to repay what they owe us then we should forgive the debt, count what they owed as a gift.
If things change there may be other ways to apply this passage to our lives or other ways to interpret what God is asking us to do, but we always try to do our best to apply the way that God has revealed himself in history to our lives and practice today in the hopes that we can work our way more into a way of living that God desires.