It is narrated from Abu-Zar and Salman that the Messenger of Allah (ص) said:
"Truly, this man is the first person of the Ummah to believe in me, and he will be the first person who will shake hands with me on the Day of Resurrection, and he is the “Siddiq-e-Akbar” (the greatest truthful) and the “Farouk” (separator of right from wrong) of the Ummah who separates and distinguishes the truth from falsehood, and he is the marvel (leader) of the believers while wealth is the marvel of the oppressors"
Mutakki Hindi, Kanz al-Ummal, V.11, page 616; Haythami, Maj’mah al-Zawaid, V.9, page 102; Ibn Hajar al-Asqalani, Lisan al-Mizan, V.2, page 414. Also, see Ibn Maghazli, Manaqib, page 180. He narrates with transmission that the Messenger of Allah (s.a.w.a.) said: ‘O Ali! You are the head of the Muslims, the leader of the pious, chief of the radiant faces and the divine master.’ Refer to Ibn Asaker, Tarikh Madinah-Damishq, V.42, page 41 and what they have narrated about the hadith.