All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
First of all, it should be mentioned that this Thikr (mentioning and remembrance) of Allaah is reported by Al-Khateeb Al-Baghdaadi in his book entitled "At-Taareekh", but Shaykh Al-Albaani classified it as Dha’eef (weak).
Nonetheless, despite the weakness of the Hadeeth, it is permissible for a Muslim to recite this repeatedly as it is permissible to act according to a Dha’eef Hadeeth in regard to Fadhaa’il Al-A’maal (righteous deeds) if it is included within a general principle of the Sharee‘ah, and the one who recites it will be rewarded, if Allaah wills. For more benefit, please refer to Fatwa 166199.
After clarifying that this Hadeeth is Dha’eef, Ibn ‘Abdul-Barr said in "At-Tamheed": “It is a good Hadeeth and its blessing is hoped for, Allaah willing.”
The Hadeeth itself includes the merits that one gets when he recites this mention, meaning, the remaining part of the Hadeeth reads: “…It will be for him a protection from poverty, and a protection from the loneliness of the grave, and a means of becoming rich, and a way to knocking on the doors of Paradise [i.e. it is a means that will lead a person to entering Paradise].”
In general, a Muslim has but to perform good deeds and Allaah will guarantee for him the reward. Allaah Says (what means): {So whoever does an atom’s weight of good will see it. And whoever does an atom’s weight of evil will see it.}[Quran 99:7-8] Allaah also Says (what means): {Indeed, Allaah does not allow to be lost the reward of the doers of good.}[Quran 9:120]
Allaah Knows best.