1 Corinthians 7:26

I suppose therefore that this is good for the present distress, I say, that it is good for a man so to be KJV

Then: Paul abandons his short break from marital issues. The Corinthians have had time for the overall precept to sink in, yet he shows it again. "Stay as you are - unmarried" because that's where you were when first called and your service there is worthy. Being single and being celibate frees one to focus on the Lord's kingdom. Then as he returns to other aspects of marriage, the Corinthians stand on solid ground, more ready to hear and understand exceptions.

Now: Matthew Henry believes first-century Christians needed strength in order to endure their never-ending persecutions. Being single allowed for that - giving more time to consider and trust Paul's knowledge and apostolic authority. Hayes (p. 127) brings up a second reason. Paul believed that the time of the end was near. Believers had very little time left to teach Christ and bring lost souls into the kingdom. When one is married, individuals have less dedicated time for evangelism. N. T. Wright adds another bit of information. The Roman world was experiencing a time of famine. That kind of distress would make it quite difficult for anyone to change social status and begin supporting a wife. Although the concept of Christ's imminent return has stretched across 2000 years, These three points continue to be concerns for anyone holding a Christian world view and thinking about marriage.

Extra Source: Commentary on the Whole Bible (Acts to Revelation) by Matthew Henry, online see http://www.ccel.org/ccel/henry/mhc6.iCor.viii.html
First Corinthians by Richard B. Hayes (John Knox Press, 1997) on line at http://books.google.com/books?id=M_PC0PAs3VYC&printsec=frontcover&dq=Corinthians+and+Hays&source=bl&ots=7aeR1egDEE&sig=izrkRudbkn01ObeyAn0mRa4mn7Y&hl=en&ei=IxBaS6PsKsXp8Qbqr4D8BA&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBgQ6AEwAw#v=onepage&q&f=false