What is the Supplication of the Throne? And what is its merit?

If the intention behind "Du'a al-Arsh" is the supplication for distress, then it is what Al-Bukhari and Al-Tirmidhi narrated from Ibn Abbas, may Allah be pleased with them, that the Prophet, peace and blessings be upon him, used to supplicate during distress with the words: "There is no god but Allah, the Most Great, the Most Forbearing. Lord of the heavens and the earth, and Lord of the Magnificent Throne." Al-Munawi said: "This is a glorious supplication that should be taken care of and recited frequently during great calamities." Ibn Jarir said: "The Salaf used to supplicate with it and called it the supplication for distress."