Hadeeth: The foremost (among believers) are three: Joshua son of Nun [of the tribe of Ephraim – tr.] who was the foremost to believe in Moses the believer implied in Surat Yasin [Chapter 36 of the Holy Qur’an] who was the foremost to believe in Jesus and `Ali ibn Abu Talib who was the foremost in believing in Muhammad (sallalahu alaihi wa ala alihi wa sallam). (Murajiat Letter 48, hadith #36).
This narration is extremely weak. (“Silsila ad-daeefa” 358). It was narrated by Tabarani from ibn Abbas, al-Heythami said in “Majmau zawaid” (#14598): “In it (it’s mean chain) Hussaid ibn Hasan al-Ashqar, he was authenticated by ibn Hibban, and weakened by majority. Other narrators people, whose ahadeth are hasan or saheeh”. Badrutdin al-Ayni in “Umdatul Qari” (16/27) said: “In the chain Hussain ibn Hasan al-Ashqar, and he’s weak”. Ibn Kathir in his commentary (6/574, shamela) said: “And this hadith is munkar, it’s not known from any way other than from Hussain al-Ashqar, and he’s shia, abandoned, and Allah knows best”. Suyote in “Durr al-mansur” (7/52) quoted this hadith from Tabarani and ibn Mardaweyh, and noticed its weakness. It was also weakened by hafidh Zaynutdin al-Iraqi.
From myself I have to notice that in the chain of Tabarani (al-Kabir, vol 11, #11152, shamela), next to al-Ashqar, we can see Hussain ibn Abu Sarra al-Asqalani. He was accused in lie by his own brother, and Abu Aruba al-Harrani. Abu Dawud said he’s weak (“Mizanul itidal” 1/536/#2003).