The additional narrations added by Abu Ya'qub occupy parts three and four of the current editions and contain the narrations from al-Rabi' on theological questions, all of which are included in part three. In part four, there are the narrations of Abu Sufyan Mahbub b. al-Rahil from al-Rabi', narrations of Imam 'Abd al-Wahhab b. 'Abd al-Rahman b. Rustam from Abu Ghanim Bishr b. Ghanim al-Khurasani, and the marasil of Jabir b. Zaid. In these marasil, the authority for transmission between Jabir and the Prophet is not mentioned.
The number of the Traditions added by Abu Ya'qub in parts three and four are 263 including 82 traditions of marasil Jabir b. Zaid. Thus The Ibadhi collection with the additions of Abu Ya'qub contains 1005 Traditions.
The Ibadhi collection of hadith is much less in number than the Sunni collections of hadith. The material of the Musnad of al-Rabi' b. Habib is the same as the material reported by Sunnis in their collections. Most of the Traditions reported by al- Rabi' b. Habib are reported by other Sunni authorities with the same wording, or with slight differences.
Al-Salimi, in his commentary on the Musnad, pointed out the Traditions reported in a unique form not found in the Sunni collections, but there are still similar Traditions expressing the same views, technically called Shawahid. On the other hand, the Ibadhi collection contained a number of Traditions, each reported with its sound Isnad of the Ibadhi authorities, which nevertheless were not accepted in the Sunni collections. Some of them have been described as being invented (mawdu'). The same is the case with a number of Traditions regarded as authentic by the Sunni authorities, but which were, to Ibadhi authorities, no more than plains lies or innovations (bida').
"Know that this honorable Musnad (compilation of hadith) has the most authentic narrations (riwayah) and the highest chain of transmitters (isnad). And all of its narrators are famous with knowledge, devout, accuracy, honesty, integrity, and preservation. All of them are imams in religion and leaders of the rightly guided."
Imam Abdullah Al-Salimi
· Al-Jami'i Al-Sahih Musnad Al- Imam Al-Rabii ibn Habib
· Studies in Ibadhism- al Ibadiyah by Amr Ennammi
· The Doctrines of the Ibadhi Creed Till the End of the Second AH Century; by Musallam Salim Al-Wahibi