Ahmad ibn Muhammad ibn Isa from al-Barqi from Sa‘d ibn Sa‘d al-Ash‘ari from Abu al-Hasan al-Ridha عليه السلام, peace be upon him, who said: I asked Him عليه السلام about the prostration of gratitude (Sajdat al-Shukr). Imam عليه السلام said: “What is the prostration of gratitude?” So I said to Him عليه السلام: “Our companions perform one prostration after the obligatory prayer and say that it is the prostration of gratitude.” Imam عليه السلام said: “Gratitude is only when Allah سبحانه وتعالى, the Exalted, bestows a blessing upon His عليه السلام servant, that he says: ‘Glory be to the One Who has subjected this to us, and we were not capable of mastering it. And indeed, to our Lord عز وجل we shall surely return.’ And all praise belongs to Allah سبحانه وتعالى, Lord of the worlds.”