Now, brother, I have applied these things to myself and Apollos for your benefit, so that you may learn from us the meaning of the saying, 'Do not go beyond what is written.' Then you will not take pride in one man over another. For who makes you different from anyone else? What do you have that you did not receive? And if you did receive it, why do you boast as though you did not?"
Leave the judgement to God
It is tempting to judge fellow Christians, evaluating whether or not they are good followers of Christ. But ONLY God knows a person's heart and he is the only one who has the right to judge. This is also a warning to us. Because when you judge another you invariably consider yourself better.
The 2nd point in this passage is to consider how leadership in the church can cloud who the true leader in the church should be. Christ should ALWAYS be the top priority. Of course we have favorite leaders in our churches, but any true spiritual leader is a representative of Christ and has nothing to offer that God hasn't given him or her.