Mustadrak al-Hakim — Hadith 8628

It is narrated from Abu Idris al-Khawlani (may Allah have mercy on him) that he said: I met Sayyiduna Abu al-Darda (may Allah be pleased with him) and gained knowledge from him, and I met Sayyiduna Ubadah bin al-Samit (may Allah be pleased with him) and memorised hadiths from him; however, I did not get to meet Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him). So Yazid bin Amirah informed me that in every gathering in which Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) sat, he would say: 'Allahu hakamun qistun, tabaraka ismuhu, halaka al-murtabun' (Allah is a just and equitable Judge, blessed is His Name; those who doubt have perished). (He would further say:) "Indeed, after you there will come trials in which wealth will be abundant, and the Qur'an will be opened up (its reading made so common) that men and women, free and slave, young and old will all acquire it. Soon a man will read the Qur'an and will say (to himself): 'I have read the Qur'an, so what is the matter with people that they do not follow me, even though I have read the Qur'an?!' Then he will say: 'They will not follow me until I invent for them something new (an innovation) other than the Qur'an.' So beware of your self-made new matters (innovations), for every invented new matter is misguidance. And beware of the slip of the wise man (hakim), for Satan casts words of misguidance upon the tongue of the wise man, while sometimes he makes a word of truth flow upon the tongue of the hypocrite." (Yazid bin Amirah said:) We said: "(O Mu'adh!) May Allah have mercy on you, how will you know that the hypocrite is speaking the truth and that Satan has cast a word of misguidance upon the tongue of the wise man?" He said: "Avoid every ambiguous (confusing) statement from the speech of the wise man, the kind about which, when you hear it, you exclaim: 'What is this?' But do not turn away from that wise man entirely (merely because of this slip), for it is quite possible that he will retract his statement and be granted the truth again. So listen to the truth, for upon the truth there is a light."
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.