In his The New Testament: a new translation, James Moffatt rendered 1 Cor 4:6 as:
Now I have
applied what has been said above to myself and Barnabas to teach you . . . *
that you are not to be puffed up with rivalry over one teacher as against
another.
In the note to the above, we read:
* The text
and the meaning of the phrase between μαθητε and ινα μη are beyond recovery.
For more on 1 Cor 4:6, see:
Not By Scripture Alone: A Latter-day Saint Refutation of Sola Scriptura