Nothing will fill the belly of the son of Adam except dust, and Allah is forgiving to him who is repentant." This text is known to be a "hadith" from Muhammad. (Bukhari, VIII, No. 444-47.) According to Ibn 'Abbas (No. 445) and 'Ubay (No. 446) this text was at times thought to be part of the Quran. However, Ubay himself clarifies that after sura 102: "I had been revealed, [the sahaba] did not consider the above to be part of the Quran." (Bukhari, VIII, No. 446.) This explanation of Ubay also makes it very clear that the companions of Mohammad did not differ at all about what was part of the Quran and what was not part of the Quran when the revelation had ceased. It is also important to note that the "hadith" appeared in the "mushaf" of Ubay because it was for his own personal use; that is, in his private notebook, where he did not always distinguish between Quranic material and "hadith", since the notebook was not meant for public use and he himself knew well what to make of his own notes. All companions of Mohammad are said to have had their own copies of the Quran, with notes, for personal use. The Islamic reports of these copies of the Quran of the companions of Mohammad only tell of various differences according to reports that reached them ("e.g.", the "hadith" in Bukhari, VIII, No. 446, that Ubay at some early stage held this sentence to be part of the Quran). However, the tangible manuscripts of these copies of the Quran have not survived but were destroyed, having been considered obsolete. After Uthman had the other codices destroyed there were still variations in the reading and the text of this Quran. However, scholars deny the possibility of great changes of the text arguing that addition, suppression or alteration would have led to controversy 'of which there is little trace'. They further state that even though Uthman became unpopular among Muslims, he was not charged with alteration or mutilation of the Quran in general. During the manuscript age, the Quran was the most copied Arabic text. It was believed that copying the Quran would bring blessings on the scribe and the owner. The Arabic script as we know it today was unknown in Muhammad's time (as Arabic writing styles have progressed through time) and the Quran was preserved through memorization and written references on different materials.