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.
darimi:175Muḥammad b. al-Ṣalt > Ibn al-Mubārak > Ibn ʿAwn > Muḥammad > ʿUmar Liāb. Masʿūd Alam

[Machine] Omar said to Ibn Mas'ud, "Did I not inform or was I not informed that you give fatwas even though you are not a ruler? Beware of who you appoint as a ruler."  

الدارمي:١٧٥أَخْبَرَنَا مُحَمَّدُ بْنُ الصَّلْتِ حَدَّثَنَا ابْنُ الْمُبَارَكِ عَنِ ابْنِ عَوْنٍ عَنْ مُحَمَّدٍ قَالَ قَالَ

عُمَرُ لِابْنِ مَسْعُودٍ «أَلَمْ أُنْبَأْ أَوْ أُنْبِئْتُ أَنَّكَ تُفْتِي وَلَسْتَ بِأَمِيرٍ؟ وَلِّ حَارَّهَا مَنْ تَوَلَّى قَارَّهَا»