Sayyidunā Ali رضي الله عنه said: “The Abdal are in Syria, and they are 40 men. Whenever one of them dies, Allāh substitutes another in his place. By means of them, Allāh brings down the rain, gives victory over enemies, and diverts punishment from the people of Syria.”
“The earth will never be empty of 40 men who are similar to the Intimate Friend of Allah (Sayyidunā Ibrāhīmعليه السلام).
By them rain falls and victory is granted. Not one of them dies except that Allah replaces him with
Qatada said, “We do not doubt that Hasan al-Basri is one of them.”
(Tabarani in Mu’jam al-Awsat (4:247 #4101) and al-Kabir (10:224 #10390) Abu Nu’aym (Ma’rifat as-Sahaba #4013). Hadith Hasan)