Over the last while, a number of people have asked me about the practice of self examination prior to partaking of the Lord's Supper. Self examination prior to partaking is certainly commanded of us (1 Cor. 11:27-34). However, there is a common and long standing idea in the evangelical church that we are to examine ourselves to see if there is any outstanding or unconfessed or unresolved sin issues in our lives and if there are, we are to exempt ourselves from the table until those sin issues have been resolved. I think this is a confusion between and a jumbling up of the above instructions by Paul and the teaching by Jesus on making things right with a brother before bringing a gift to the altar in the temple (Matt. 5:23-24). It needs to be said that these are two different situations. In Paul's instructions, we don't see Christians being told to temporarily excommunicate themselves from the table until they've gotten their sanctification act together. Rather, in its context, Paul's instruction is one of examining one's overall loyalties. Are they to Christ or are they to sin?
Doug Wilson has some helpful words on what we are looking for when we examine ourselves prior to partaking of the Lord's Supper.