The key passage concerning debt relief is found in Deuteronomy 15, which states in verse 4 God's intention that "There will be no one in need among you." Verses 1-11 deal with the remission of debts in the Sabbath Year, and verses 12-18 with the freeing of slaves in the Sabbath year. Both mandates are based on the exodus.
"Remember that you were a slave in the land of Egypt, and the Lord your God redeemed you; for this reason I lay this command upon you today." (Deuteronomy 15:15) Clearly it would be a glaring contradiction for a liberated people, people of the liberating God Yahweh, to practice slavery!
In ancient times the principal mechanisms of poverty and oppression were debts, inevitable whenever crops failed, and slavery, the result of one's inability to repay debts. The Sabbath Year mandates were designed to intervene and offer a new beginning for the poor and oppressed, which is precisely what the poor and oppressed need today.
Don't we have to remember this mandate, too, when we pray the Lord's Prayer and say "Forgive us our debts, as we forgive our debtors"? (Matthew 6:12) This does not mean merely to cancel loans every seventh year. As many Third World peoples and disadvantaged peoples in the U.S. have pointed out so poignantly, our depts to them and their ancestors are astronomically far beyond anything they may owe us under current debt arrangements.
The first Christians evidently eliminated each others' debts, as they shared all their possessions, and "there was not a needy person among them." (Acts 4:34, cp Deuteronomy 15:4) Sabbath economics requires a personal lifestyle and a socio-economic order that will prevent and overcome poverty.