Protestants often use 1 Corinthians 4:6, which says “not to go beyond what is written,” in order to support Sola Scriptura. What is the Catholic interpretation of this passage?
This was taken from a non-Catholic commentary (Pulpit Commentary), the thoughts seem to be consistent in many commentaries, Catholic or not - what your friends suggest is a misinterpretation:**
Not to think of men above that which is written**. The true reading is merely, not above the things which have been written,as though the words were a sort of proverb, like Ne quid nimis or Milton’s “The rule of not too much” (μσηδὲν ἄγαν). The word “to think” is omitted in the best manuscripts. The phrase, “which have been written,” is of very uncertain meaning. It may refer generally to “the scriptural rule” that all boasting is wrong (Jer. 9:23), or to the humble estimate of teachers which he has just been writing down for them. All his Old Testament quotations so far (ch. 1:19, 31; 3:19) have referred to humility. The text, like so many others, has only a very remote connection with the sense in which it is usually quoted%between% %between%
First, read the context of those words. Those words were to the Corinthians who some were becoming puffed up in pride and going beyond the written instructions given to them. So Paul was sending them a teacher to be there all the time.
Second, if you are going to pick and choose, what about :bible1: 2thessalonian 2:15 “hold fast to traditions, oral or by letter”
There are more, I will try to come back or others can catch you up.
Or look here scripturecatholic.com/oral_tradition.html#oral-II