It has been mentioned in the book, Balad al-Amin and the Misbah of Kafa mi that Imam Ali ibn al-Husain Sayyid as-Sajjidin related from his father from his grandfather the Prophet of Allah that this supplication was taught by the Angel Jibra'il to the Prophet during one of the battles.
It was in one of the wars that the Prophet had taken part in which he had a very heavy and expensive coat of armor on to protect himself."O' Muhammad! Your Lord conveys his salutations to you and has said to take this coat of armor (Jawshan) and to recite it as this is a protection for you and your Ummah."
At this point, the Angel continued to give the Prophet an explanation on the greatness of this supplication, which we will omit from here due to lack of space.
However it suffices us to state that whoever reads this supplication with a pure intention in the BEGINNING of the month of Ramadhan, Allah will grant him sustenance on the Night of Power and will create for this person 70,000 Angels who will all be busy in the praising and glorification of Allah and will give this reward to the person who has read this supplication.
"My father Amir al-Mo'minin Ali ibn Abi Talib had bequeathed to me that I should memorize and protect this supplication and write it on the Kafan (burial shroud) and that I should teach it to my family members and he highly encouraged me to read this supplication as it contains 1,000 names of Allah and within these names is the Greatest Name of Allah (Ism-e-A dham)."