The Peak of Eloquence · Hadith 2042 (#Passage #401)

٣٢٤. وَقَالَ (عليه السلام): اتَّقُوا مَعَاصِيَ اللهِ فِي الْخَلَوَاتِ، فَإِنَّ الشَّاهِدَ هُوَ الْحَاكِمُ.

324. Amīr al-mu’minīn, peace be upon him, said: Beware of disobeying Allāh in solitude, because the witness (of that situation) is also the judge.

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).