سنن ابو داؤد #834

The above-mention tradition has also been transmitted through a different chain of narrators by Humaid, but he did not mention the word “Supererogatory prayer” This version has:Al-Hasan (al-Basri) would recite fatihat al-kitab in the noon and afternoon prayers while he led in prayer or he was behind the imam and would glorify Allah, and would repeatedly say: “Allah is most great” and “ There is no god but Allah” (i.e takbir and tahlil) equal to the amount one recites al-Qaf (Surah 50) and al-Dhariyat(surah)