Owe no man any thing, but to love one another: for he that loveth another hath fulfilled the law.
Note 1 at Ro 13:8: In context, Paul was speaking about paying our taxes, respect, and honor (Ro 13:7). However, this principle holds true in every area of our lives. We are to pay our bills.
Some people have interpreted this verse as forbidding Christians to go in debt. It can be shown in Scripture that purchasing on credit is not a blessing but a curse (De 28:12 and 44); therefore, it is not God's best. However, it is not a sin to borrow money. Many scriptures speak of lending money and place restrictions on whom we should lend to. The Lord would not have us help someone sin.
Therefore, being in debt is not a sin. Failure to pay our bills or make payments on loans that we have given our word on, however, is wrong.
Note 2 at Ro 13:8: Notice that Paul spoke of love for others as a debt. This is not optional. We are commanded to love one another. Indeed, this is the royal law of God (Jas 2:8).
Note 3 at Ro 13:8: Mankind as a whole had misunderstood the purpose of the Law. They thought that God was giving a list of what people must do to be accepted by Him. But the Law was given to convince people that they didn't have a chance of saving themselves; they needed a savior (see note 4 at Ro 3:19).
However, the Law was accurate and a perfect description of what God created man to be. The Law portrayed what those who were walking in God's kind of love would do. Man still can't keep the Law perfectly in the flesh (see note 9 at Ro 8:4), but the New Testament believers can now fulfill the spirit of the Old Testament Law as those in the Old Testament never could.