Alsiraj Official Website
Sayings (Hadiths) of Prophet Muhammad
Why Hadith was not generally written
It is, however, a fact that the sayings of the Holy Prophet were not generally written, and memory was the chief means of their preservation. The Holy Prophet sometimes objected to the writing down of Hadith. Abü Huraira is reported to have said: “The Prophet of God came to us while we were writing Hadith and said, What is this that you are writing? We said, Hadith which we hear from thee. He said, What! a book other than the Book of Allah?" Now the disapproval in this case clearly shows fear lest hadith be mixed up with the Holy Qur’an, though, there was nothing essentially wrong in writing down Hadith, nor did the Holy Prophet ever forbid its being done.
On the other hand, as late as the conquest of Makka, we find him giving orders himself for the writing down of a certain hadith at the request of a hearer. He also wrote letters, and treaties were also put down in writing, which shows that he never meant that the writing of anything besides the Qur’an was illegal. What he feared, as the report clearly shows, was that if his sayings were written down generally like the Qur’an, the two might get confused together, and the purity of the text of the Holy Qur’an be affected.