Mishkat al-Masabih 141
Jabir reported God’s messenger as saying, “To proceed:
The best discourse is God’s Book, the best guidance is that given by Muhammad, and the worst things are those which are novelties. Every innovation is error.” 

Muslim transmitted it.
وَعَنْ جَابِرٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «أَمَّا بَعْدُ فَإِنَّ خَيْرَ الْحَدِيثِ كِتَابُ اللَّهِ وَخَيْرَ الْهَدْيِ هَدْيُ مُحَمَّدٍ وَشَرَّ الْأُمُورِ مُحْدَثَاتُهَا وَكُلَّ بِدْعَةٍ ضَلَالَةٌ» . رَوَاهُ مُسْلِمٌ