Al-Kāfi - Volume 1 > The issue that Allah’s holding people accountable remains unjustified without the Imam
Hadith #3

3ـ أَحْمَدُ بْنُ مُحَمَّدٍ عَنْ مُحَمَّدِ بْنِ الْحَسَنِ عَنْ عَبَّادِ بْنِ سُلَيْمَانَ عَنْ سَعْدِ بْنِ سَعْدٍ عَنْ مُحَمَّدِ بْنِ عُمَارَةَ عَنْ أَبِي الْحَسَنِ الرِّضَا (عَلَيْهِ السَّلام) قَالَ إِنَّ الْحُجَّةَ لا تَقُومُ لله عَلَى خَلْقِهِ إِلا بِإِمَامٍ حَتَّى يُعْرَفَ.

3. Ahmad ibn Muhammad has narrated from Muhammad ibn al-Hassan from ‘Abbad ibn Sulayman from Sa‘d ibn Sa‘d from Muhammad ibn ‘Ammara from abu al-Hassan al-Rida (a.s.) who has said the following. “Allah’s holding people accountable remains unjustified without the Imam who would teach people about Him.”