The debtor was to deliver up as a pledge to the creditor what he could most easily dispense with (Deuteronomy 24:10,11).
A mill, or millstone, or upper garment, when given as a pledge, could not be kept over night (Exodus 22:26,27).
A debt could not be exacted during the Sabbatic year (Deuteronomy 15:1-15).
For other laws bearing on this relation see Leviticus 25:14,32,39; Matthew 18:25,34.
A surety was liable in the same way as the original debtor (Proverbs 11:15; 17:18).
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain, copy freely.
Easton, Matthew George. "Entry for 'Debtor'". "Easton's Bible Dictionary".