That specific phrase is present in the New International Version:
Now, brothers and sisters, 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 be puffed up in being a follower of one of us over against the other.
The meaning of the part of the verse you quoted is fairly clear: God's word is sufficient. Do not invent more of it.
I'm not sure if about commentary from early scholars, but there is English commentary from several Reformation-era scholars. Of course, they often commented using the King James version:
And these things, brethren, I have in a figure transferred to myself and to Apollos for your sakes; that ye might learn in us not to think of men above that which is written, that no one of you be puffed up for one against another.
Matthew Poole (17th century):
And these things, brethren, I have in a figure transferred to myself and to Apollos for your sakes: by these words the apostle lets us know, that though he had said, 1 Corinthians 1:12, that some of them said, "We are of Paul, and others: We are of Apollos"; yet the names of Paul and of Apollos were but used to represent other of their teachers, which were the heads of those factions which were amongst them. In very deed there were none of them that said, "We are of Paul or of Apollos", (for those that were the disciples of Paul and Apollos were better taught), but they had other teachers amongst them as to whom they made factions, whom Paul had a mind to reprove, with their followers...
That you might learn in us not to think of men above that which is written; and that (as the apostle saith) all the church of Corinth, as well ministers as people, might learn to have humble opinions and thoughts of themselves, not to think of themselves above what, by the rules of God’s word, was written in the Old Testament they ought to think; or above what he had before writen in this Epistle, or to the Romans...
In other words, Paul used the hypothetical phrases "I am of Paul" and "I am of Apollos" (mentioned earlier in the epistle) to demonstrate the folly of relying on manmade words of the teacher more than than the God-made words of the scripture, and using those manmade differences as a source of pride.