How may a worshiper supplicate in prostration after saying "Subhana Rabbiyal A'la" three times in a supererogatory prayer? And is there a voluntary prostration other than the prostration of thankfulness and the prostration of recitation? And what is said in the prostration of thankfulness?

Prostrating in gratitude (Sujud al-Shukr) requires saying "Subhana Rabbiyal-A'la" (Glory be to my Lord, the Most High), according to the Hanbalis. It is not prescribed to perform a solitary prostration other than the prostration of recitation (Sujud al-Tilawah) and the prostration of gratitude, as there is no religious text supporting it.