Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
ahmad-zuhd:1557ʿAbdullāh > Rawḥ > ʿAbd al-Muʾmin b. Abū Shurāʿah > al-Ḥasan

[Machine] "Recognize the emigrants for their virtue, follow their footsteps, and beware of what people have newly introduced in their religion, for indeed, the worst of matters are those that are newly invented."  

الزهد لأحمد:١٥٥٧حَدَّثَنَا عَبْدُ اللَّهِ حَدَّثَنَا رَوْحٌ حَدَّثَنَا عَبْدُ الْمُؤْمِنِ بْنُ أَبِي شُرَاعَةَ عَنِ الْحَسَنِ قَالَ

«اعْرَفُوا الْمُهَاجِرِينَ بِفَضْلِهِمْ وَاتَّبِعُوا آثَارَهُمْ وَإِيَّاكُمْ وَمَا أَحْدَثَ النَّاسُ فِي دِينِهِمْ فَإِنَّ شَرَّ الْأُمُورِ الْمُحْدَثَاتُ»