The answer is that the hadith does not state that, by reciting this remembrance, a servant has fully discharged his duty to Allah, duly thanked Him for His blessings, or offered anything commensurate with them! At most, it indicates that he has uttered a remembrance equivalent to all the praise offered by those who praise Allah. This is an instance of rewards being multiplied.
This is further confirmed by the fact that the praise of all creation neither fulfils their duty to Allah nor matches His blessings upon them. For there is no end to the thanks due to Allah—exalted be He—just as there is no end to His greatness.
This assumes that the additional wording, “has praised Allah with all the praise offered by all creation,” is not found to be defective, for the basic hadith appears in the Musnad, the Sunan collections and elsewhere without this addition!
Attribution of the Fatwa to Ibn al-Qayyim
Several considerations establish with certainty that this fatwa is attributable to Ibn al-Qayyim (may Allah have mercy on him):
First: The author’s name appears at the beginning of the fatwa. The manuscript’s copyist wrote:
“Our shaykh, the imam and scholar, the exemplar of meticulous scholars, the mainstay of hadith scholars, the luminary of the faith and religion, Abū ‘Abd Allāh Muhammad ibn Abī Bakr al-Qayyim—may Allah envelop him in His mercy—gave the following answer.”
Second: He mentions Shaykh al-Islām Ibn Taymiyyah (may Allah have mercy on him) at several points in the treatise and almost refers to him as “our shaykh”; and Ibn al-Qayyim’s discipleship under Shaykh al-Islām