1Corinthians 1:11-13 For it hath been declared unto me of you, my brethren, by them which are of the house of Chloe, that there are contentions among you. (12) Now this I say, that every one of you saith, I am of Paul; and I of Apollos; and I of Cephas; and I of Christ. (13) Is Christ divided? was Paul crucified for you? or were ye baptized in the name of Paul?
Here was a struggle in the church of Corinth. There were divisions because members were worshiping a certain man and his particular style of preaching. Paul greatly rebukes this in the next several chapters making the point that we don't worship MEN. We are not "OF" men. Men who are spiritually gifted are to be imitated, listened to, learned from, respected, and even obeyed - but not to cause factions or groups to themselves.
Frankly, this is always a temptation within the body of Christ. It comes from Preachers who may struggle with the temptation of pride that comes when people listen to them and value them over other fellow Ministers. Also, there is a tendency that we all have to want to exalt and rally around those who make an impact on us. There is a loyalty that starts with good motives, but may grow to a faction that pulls the attention away from Jesus Christ and places it on men who are supposed to be His slaves! It is often easier to focus on men who we can follow physically than Christ whom we must pursue spiritually.
By inspiration, the writer simply says "Is Christ divided?" - the answer to that is "NO!" When there are divisions within the church following certain leaders or even laymen, we have taken our eyes off of the Goal. That Goal is Christ.