What is the authenticity of the narration reported from Malik bin Dinar concerning the story of the black man who supplicated to Allah, and as a result, Basra was watered, and is there anything in it that is not permissible to say?

The story mentioned was narrated by Ibn al-Jawzi in "Sifat al-Safwah" from Malik bin Dinar without a chain of narration, and its authenticity is unknown. It is a story of soft admonition and not a prophetic hadith, and the answering of prayers in it is not strange, for some of God's servants, if they were to swear an oath by Him, He would fulfill it for them. What is prescribed during drought is the prayer for rain (Salat al-Istisqa).