One day Muhammd (SAW) was sitting in the Masjid and Hazrat Jibreel (A.S) brought Dua Ganj-ul-Arsh to Rasulullah Sall Allahu alaihi wa Aalihi wa Sallim. Hazrat Jibreel Alaihi Salaam said that in addition to a lot of Fadhaail [favors] in this Dua', the reciter gets three things from Allahu ta 'ala.
Firstly, Allah (SWT) gives him rizq [livelihood] from the ghayb [unknown sources], secondly, He will safe from evil eye and evil spells and thirdly, whoever recites Dua Ganj-ul-Arsh his enemies will not be able to overcome him. He will be superior to them.
The person who does jihad will have the upper hand. He goes on a journey, he will come back with all his things. He will be safe from the shaat of shaytaan. He will be safe from all the bad things and insects and other things on earth and all the bad things in the skies.
If a person writes this Dua out and drinks it using rain water, he will get help for various diseases. If a person suffers from an unknown illness for which the worldly doctors can find no cure and he writes it with Zafran [saffron] and washes it and drinks it for twenty one (21) days he will get health. If he doesn't have children, he will get children with the help of Dua Ganj-ul-Arsh.