1 Corinthians 6:8

Nay, ye do wrong, and defraud, and that your brethren (KJV)

Then: Remembering the corruptness of the Roman system, Corinthians may be getting the glimmer of an idea that they themselves are corrupt. They avoid Christ's guidelines, object to participating in a church forum, and depend on the skewed value judgements of non-believers because they know they will win their lawsuits. There's not much difference between themselves and the pagans (Fee, p. 241). It's even worse because they are cheating their brothers in Christ.

Now: Matthew Henry allows a little room for Christians to use the secular law system. If there is a matter such as an unclear boundary line and the two parties amicably agree, then trained lawyers should be called upon to make a determination. There are probably other instances in which the Christians have no choice, but as often as possible they should follow Jesus' words to agree quickly with the opponent lest you lose more than imaginable.

Extra source: The First Epistle to the Corinthians by Gordon D. Fee (Eerdman's 1987) online at http://books.google.com/books?id=XlBp10nUTXAC&dq=Gordon+Fee+Bible+commentator&printsec=frontcover&source=in&hl=en&ei=SwLNSu3nA4v6Mf2XlDo&sa=X&oi=book_result&ct=result&resnum=12#v=onepage&q=&f=false
Commentary on the Whole Bible Acts to Revelation Vol VI by Matthew Henry online at http://www.ccel.org/ccel/henry/mhc6.iCor.vii.html