Is it permissible to supplicate with supplications that are not authentically attributed if they do not contain anything that violates Islamic law? And is the Hadith "There is no god but Allah, the Sovereign, the Manifest Truth. Whoever says it a hundred times a day will have it as a safeguard from poverty and from the loneliness of the grave, and thereby acquire wealth, and knock on the door of Paradise" authentic?

There is no harm for a Muslim to supplicate to his Lord with any prayer, whether it is transmitted [from the Prophet] or not, or if its chain of narration is not established, provided that it does not involve sin or severance of kinship ties. The saying "La ilaha illallah, al-Malik al-Haqq al-Mubin (There is no god but Allah, the King, the Manifest Truth)" is considered a blessed remembrance, even though the hadith (definition) reported concerning it has a weak chain of narration. Prayers mentioned in the Quran and Sunnah (definition) are preferred due to their comprehensiveness and benefit for the servant in this world and the Hereafter, especially for those who cannot distinguish between permissible and impermissible supplications.