Laudator Temporis Acti

1 Corinthians 4:6 (Revised Standard Version):

I have applied all this to myself and Apollos for your benefit, brethren, that you may learn by us not to go beyond what is written, that none of you may be puffed up in favor of one against another.

ταῦτα δέ, ἀδελφοί, μετεσχημάτισα εἰς ἐμαυτὸν καὶ Ἀπολλῶν δι' ὑμᾶς, ἵνα ἐν ἡμῖν μάθητε τό μὴ ὑπὲρ ἃ γέγραπται, ἵνα μὴ εἷς ὑπὲρ τοῦ ἑνὸς φυσιοῦσθε κατὰ τοῦ ἑτέρου.

τό μὴ ὑπὲρ ἃ γέγραπται del. Frid. Aug. Bornemann, "De memorabili glossemate, quod locum I Corinth. 4, 6. insedisse videtur," Biblische Studien von Geistlichen des Königreichs Sachsen 2 (1843) 37-44 (at 37-40).

Bornemann, p. 38 (my translation):

I would like you to recognize in the words τό μὴ ὑπὲρ ἃ γέγραπται nothing but an annotation, by which the scribe wanted to indicate that in the original in front of his eyes, the negative word μή had been written above the final letter of the conjunction ἵνα, in such a way that the scribe doubted whether he should consider it as genuine or not, whether he should put it in the text or omit it.

In verbis τό μὴ ὑπὲρ ἃ γέγραπται nihil nisi adnotamentum velim agnoscas, quo librarius indicaturus erat, in archetypo, quod ipsi ante oculos erat, negationem μή literae ultimae coniunctionis ἵνα superscriptam fuisse, ita ut haesitaret scriba, pro genuina haberet necne, in textisne poneret, an omitteret.

In other words, the scribe meant to note that "μή has been written above α (of ἵνα)."

I owe my knowledge of Bornemann's conjecture to Jan Krans, Beyond What Is Written: Erasmus and Beza as Conjectural Critics of the New Testament (Leiden: Brill, 2006 = New Testament Tools and Studies, 35), p. 1, n. 2.

Joseph A. Fitzmyer ad loc. (3rd of 4 explanations of τό μὴ ὑπὲρ ἃ γέγραπται):

The words are considered to be a marginal gloss that has been introduced secondarily into the text. A scribe perceived that the negative (mē) was missing from the first hina clause, and because the text without it would have read, "Now, brother, I have transferred this to myself and Apollos for your sake, that you may learn from us to become arrogant, siding with one against another," it would flatly contradict the point that Paul has been trying to make. So the scribe emended the text, writing mē above the alpha (the final letter) of hina and calling attention to it in a marginal note, which was subsequently added to the text. Baljon (De tekst, 49–51) was among the first to propose this explanation; it has been adopted by many others: Bousset, Héring, Howard, Legault, MacDonald, Murphy-O'Connor, Strugnell, C.S.C. Williams; cf. IBNTG, 64; BDR §230.4). (Although it is not noted in the usual apparatus criticus, the mē is absent in mss D and E.) Even though this explanation seems attractive, it involves anacoluthon in the first hina clause and makes the second hina clause the obj. of the verb mathēte, which is strange. Murphy-O'Connor, acknowledging these difficulties, nevertheless considers Strugnell's translation "undoubtedly correct" and raising "the hypothesis of a gloss to the level of certitude" ("Interpolations," 85); but Kilpatrick ("Conjectural Emendation," 352) remains "unconvinced by Strugnell's suggestion"; similarly Lindemann, 1 Cor, 103.

J.M.S. Baljon, De tekst der brieven van Paulus aan de Romeinen, de Corinthiërs en de Galatiërs als voorwerp van de conjecturaalkrititiek beschouwd (Utrecht: J. van Boekhoven, 1884) (non vidi), appeared 41 years after Bornemann, who deserves credit for the ingenious suggestion.