ʿUyūn akhbār al-Riḍā
Hadith 187187 - وَبِهذَا الإسناد قالَ: قالَ رَسُولَ اللَّهِ صَلَّى اللهُعَلَيْهِ وَآلِهِ: يا عَلِيِّ لَولاكَ لَما عُرِفَ الْمُؤْمِنُوُنَ بَعْدي.
31-187 According to the same documentation, God’s Prophet (S) said, “O Ali! Were it not for your existence, the believers after me would not get recognized.”