In a narration in al-Mu'jam al-Awsat the words are: Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates concerning this saying of Allah Almighty: (Allah Almighty says:) "Or a remnant of knowledge." Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: What is meant by this is writing well. Ahmad's narrators of the marfu' hadith are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب التفسير / 11336