It should be noted that many of the narrators like Ka'b al-Akhb?

It should be noted that many of the narrators like Ka'b al-Akhb?r, were learned companions who had belonged to the Jewish faith before accepting Islam. Moreover, it should not be overlooked that Ibn Abbas usually expressed the meanings of verses in poetry. In one of his narrations over two hundred questions of Nafi' ibn al-Azraq are replied to in the form of poetry; al-Suyüti in his book, al-Itqin, related one hundred and ninety of these questions.

It is evident, therefore, that many of the narrations made by the commentators amongst the companions cannot be counted as actual narrations from the Prophet himself; therefore, such additional material related by the companions must be rejected. The second group of commentators was the companions of the followers (t?bi'ün), who were the students of the companions. Amongst them we find Muj?hid, Sa'id ibn Jubayr, 'Ikrimah and 1?ahb?k.

Also from this group were Hasan a1-Basri, 'Ata' ibn Abi Rabab, 'Ata' ibn Abi Muslim, Abü al-'Aliyah, Muhammad ibn Ka'b al-Qurazi, Qatadah, 'Atiyah, Zayd ibn Aslam, Ta'us al-Yamani13) The third group were comprised of the students of the second group, namely, Rabi' ibn Anas, 'Abd al-Rahm?n ibn Zayd ibn Aslam, Abü Salib al-Kalbi and others.

(14)The tabi'ün sometimes narrated the commentary on a verse as a tradition of the Prophet or of the companions and, sometimes, they explained its meaning without attributing a narrator to the source, this they did especially when there was any doubt as to the identity of the narrator.

The later commentators treat these narrations as of the Prophet, but count them as mawq4f in their science of the levels of hadith (that is as a tradition whose chain of narration does not reach back to the Prophet). The fourth group comprised the first compilers of commentaries, like Sufyan ibn 'Uyaynah,(15) Waki' ibn al-Jarrah, Shu'bah al-Ilajjaj and 'Abd ibn I3umayd; others from this group include Ibn Jarir al-Tabari, the author of the famous Qur'anic Commentary.

(16) This group recorded the sayings of the companions and the followers of the companions with a chain of narrators in their works of commentary; they avoided expressing personal opinions except, perhaps, Ibn Jarir al-Tabari who sometimes expressed his views by indicating his preference when discussing two similar traditions. The basis of the work of later groups may be traced to this group.