“It is related by Sa‘d bin Abī Waqās (RA):
I heard Allāh’s Messenger (SAW) say:
One who has me as his master has ‘Alī as his master.
And I heard him say (to ‘Alī (RA)): You are in my place as Hārūn was in Mūsā’s place, but there is no prophet after me.
And I also heard him say (on the occasion of the battle of Khaybar): Today I shall bestow the flag on the person who loves Allāh (SWT) and His Messenger (SAW).”
Ref: Ibn Mājah transmitted this sahīh (sound) hadīth in the preface (al-muqaddimah) to his Sunan (1:90 # 121); Ibn Abī ‘Āsim, as-Sunnah (p.608 # 1386); Mizzī, Tuhfat-ul-ashrāf bi-ma‘rifat-il-atrāf (3:203 # 3901); and Nasā’ī reproduced it with slightly different words in Khasā’is amīr-il-mu’minīm ‘Alī bin Abī Tālib (pp. 32,33 #91).