This hadith has been reported on the authority of Ibn Numair but with a slight change of words.
In-book : Book 21, Hadith 19
USC-MSA web (English) : Book 10, Hadith 3623 (deprecated)
21. The Book of Transactions
باب فِي أَنَّ الإِسْنَادَ مِنَ الدِّينِ وَأَنَّ الرِّوَايَةَ لَا تَكُونُ إِلَّا عَنْ الثِّقَاتِ وَأَنَّ جَرْحَ الرُّوَاةِ بِمَا هُوَ فِيهِمْ جَائِزٌ بَلْ وَاجِبٌ وَأَنَّهُ لَيْسَ مِنْ الْغِيبَةِ الْمُحَرَّمَةِ بَلْ مِنْ الذَّبِّ عَنْ الشَّرِيعَةِ الْمُكَرَّمَةِ