The Source of Traditions on Imam al-Riḍā (Vol 2) · Hadith 276 (#Ḥadīth #276)

276- وَبِإِسْنادِهِ عَنْ عَلِيِ a.sُ قالَ: لَقَدْعِلْمَ المُستَحفِظُونَ مِنْ أَصْحابِ مُحَمَّدٍ أَنأَهْلَ صِفِّينَ قَدْ لَعَنَهُمُ اللَّه عَلَى لِسانِ نَبِيِّهِ، وَقَدْ خابَ مَنِ افْتَرى.

31-276 According to the same documentation, on the authority of Ali ,“The loyal companions of Muhammad remember that God cursed the people of Saffayn by means of the tongue of His Prophet. It does not matter if anyone lies about this.”

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