It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Noble Prophet (peace and blessings of Allah be upon him) said: "As for the bowing (ruku'), then declare the greatness of your Lord, the Exalted, in it."

Sayyiduna Uqbah bin Amir (may Allah be pleased with him) narrates that when (this verse) «‏‏‏‏فَسَبِّحْ بِاسْمِ رَبِّكَ الْعَظِيمِ» ‏‏‏‏ [ سورة الواقعة ] (“Glorify the name of your Lord, the Most Great”) was revealed, the Messenger of Allah (peace and blessings be upon him) commanded us:“Recite it in your bowing (ruku).”

The Imam narrated from his respected teacher, Muhammad bin Isa, with his chain of transmission from Sayyiduna Uqbah bin Amir (may Allah be pleased with him), a narration similar to the one mentioned above.

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Noble Prophet (peace and blessings be upon him) lifted the curtain of his blessed chamber and saw the noble companions standing and performing prayer behind Sayyiduna Abu Bakr (may Allah be pleased with him). So the Prophet (peace and blessings be upon him) said: O Allah, have I conveyed (the religion)? Indeed, from the glad tidings of prophethood, only righteous dreams remain, which a Muslim sees for himself or are shown to him (about others). And indeed, I have been forbidden from reciting (Qur’an) in the state of bowing and prostration, so in bowing, glorify the greatness of your Lord, and in prostration, make abundant supplication, for it is more likely that your supplications will be accepted. Abu Asim narrated these words once:“The Noble Prophet (peace and blessings be upon him) lifted the curtain while the companions were standing and performing prayer behind Sayyiduna Abu Bakr (may Allah be pleased with him).”The narration of Ismail and Ibn Uyaynah is not complete with only these words; I have narrated it briefly.