It was related the Prophet ﷺ said (what means): “Whoever says everyday in the morning and evening:
حَسْبِيَ اللَّهُ لَا إِلَهَ إِلَّا هُوَ ۖ عَلَيْهِ تَوَكَّلْتُ ۖ وَهُوَ رَبُّ الْعَرْشِ الْعَظِيمِ
(which means) “Allaah’s support is enough for me; there is no god but Him; on Him I rely and He is the Lord of the great Throne” seven times, Allaah will give him enough against matters which preoccupy him of this world and the Hereafter.”
Al-Adhkaar by Imaam An-Nawawiyy, Chapter 19 on what is recited in the morning and evening, hadeeth number 204. He says: We have reported in it (the book of Ibn As-Sunniyy), through ‘Abud-Dardaa’ that the Prophet ﷺ said (what means): “Whoever says everyday in the morning and evening (what means): “Allaah’s support is enough for me; there is no god but Him; on Him I rely and He is the Lord of the great Throne” seven times, Allaah will give him enough against matters which preoccupy him of this world and the Hereafter.”
As-Suyootiyy reported the same supplication from Ibn As-Sunniyy through ‘Abud-Dardaa’ in his “Kitaab Daa^il-Falaah fee ‘Adhkaaril-Masaa’i was-Sabaah.” His narration does not include the mention of the Hereafter.
The supplication is from Soorah At-Tawbah, Aayah 129.
