Sufyan al-Thawri said: The Caliphs are five: Abu Bakr, Umar, Uthman, ‘All and Umar bin Abd al-Aziz.
Explanation & Benefits
Shaykh Umar Farooq Saeedi
Benefits and Issues:
Although the narration is weak, the general opinion is that those who truly upheld the methodology of Prophethood were these five caliphs; in other caliphates, there was some degree of deviation. Thus, this incident refers, besides the four rightly guided caliphs, to Umar ibn Abd al-Aziz (rahimahullah), who was a Tabi‘i, but Ahl al-Sunnah wa’l-Jama‘ah generally also consider him a rightly guided caliph, because he did not accept the nomination from Sulayman ibn Malik and instead gave people the right to choose their ruler through consultation (shura). The people, of their own will, chose him as Amir al-Mu’minin. Then, like the other rightly guided caliphs, he conducted the affairs of government entirely in accordance with the Qur’an and Sunnah; therefore, he too is rightly considered a rightly guided caliph. Hasan al-Basri (rahimahullah) was caliph for seven months. His period is considered part of the first rightly guided caliphate.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 4631