I Corinthians 4:4

For I know nothing by myself; yet am I not hereby justified: but he that judgeth me is the Lord (KJV)

Then: Paul examined his conscience and found nothing wrong. Actually, some Corinthians could take that stament and twist it. Maybe Paul couldn't see his transgressions, but they could. That's why Paul continues on to say that wasn't the final decision (Fee, p. 161). He could be wrong about his conduct, but the only one who could judge accurately was the Lord. Henry also notes a sense of tacit reproval which Paul directs towards the Corinthians. ("The Lord can judge me, you can't.")

Now: Writers at the Koinonia Christian Fellowship bring up the inadequacies of conscience in personal judgement. A common phrase is "Let your conscience be your guide." The problem is that consciences may cause guilt over things that are not your fault and conversely let you overlook other issues which definitely need correction. Consciences need to be trained through Bible study, interaction with fellow humans and submission before the Lord. When he has our attention, we can steadily move into a condition of being more faithful, trustworthy, and productive servants.

Extra sources: The First Epistle to the Corinthians by Gordon D. Fee (Eerdman's 1987) online 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 Volume VI (Acts to Revelation) by Matthew Henry, online at http://www.ccel.org/ccel/henry/mhc6.iCor.v.html
1 Corinthians 4 - Devotional & Commentary posted on November 19th, 2009 by Debbie Fitz in Devotions, Syndicated (Koinonia Christian Fellowship at UT Austin) online http://www.koinoniatexas.org/2009/11/1-corinthians-4-%e2%80%93-devotional-commentary/