Yazid bin Umayrah, the student of Sayyiduna Mu'adh (may Allah be pleased with him), said: Whenever Sayyiduna Mu'adh (may Allah be pleased with him) sat in a gathering of remembrance, he would say: Allah is a just Judge. And Abu al-Yaman said: "Qist" (Equitable); blessed is His name; the doubters have perished. One day, in a gathering, Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) said: Ahead of you are trials in which wealth will abound and the Qur'an will be opened up, so that the believer and the hypocrite, the free and the slave, the man and the woman, the old and the young will all take it. Soon someone will say: Why do people not follow me when I have read the Qur'an? By Allah, they will not follow me until I innovate something else for them. So beware of what is innovated, for what is innovated is misguidance. And beware of the deviation of the wise man, for Satan sometimes utters a word of misguidance on the tongue of the wise man, and the hypocrite sometimes speaks a word of truth. The narrator said: I said to him: May Allah have mercy on you! How would I know that the wise man is speaking a word of misguidance and the hypocrite a word of truth? He said: Avoid from the speech of the wise man the dubious things about which you say, 'What is this?' But let that not drive you away from him, for perhaps he will retract and accept the truth when he hears it, for upon the truth there is light. In the narration of the Qadi: "And let that not turn you away from him." Thus Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) informed that the lapse of a wise man does not make it obligatory to turn away from him, but that of his words which has no light upon it is to be left, for upon the truth there is light; meaning, and Allah knows best, an indication from the Book, the Sunnah, consensus (ijma'), or analogy (qiyas) upon some of these.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20916