وَعَنْ مُعَاذِ بْنِ جَبَلٍ: أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لَمَّا بَعَثَهُ إِلَى الْيَمين قَالَ: «كَيْفَ تَقْضِي إِذَا عَرَضَ لَكَ قَضَاءٌ؟» قَالَ: أَقْضِي بِكِتَابِ اللَّهِ قَالَ: «فَإِنْ لَمْ تَجِدْ فِي كِتَابِ اللَّهِ؟» قَالَ: فَبِسُنَّةِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «فَإِنْ لَمْ تَجِدْ فِي سُنَّةِ رَسُولِ اللَّهِ؟» قَالَ: أَجْتَهِدُ رَأْيِي وَلَا آلُو قَالَ: فَضَرَبَ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَلَى صَدْرِهِ وَقَالَ: «الْحَمْدُ لِلَّهِ الَّذِي وَفَّقَ رَسُولَ رَسُولِ اللَّهِ لِمَا يَرْضَى بِهِ رَسُولُ اللَّهِ» . رَوَاهُ التِّرْمِذِيّ وَأَبُو دَاوُد والدارمي

Mu'adh b. Jabal told that when God’s Messenger sent him to the Yemen he asked him how he would judge when the occasion arose, and he replied that he would judge in accordance with God’s Book. He asked what he would do if he could not find guidance in God’s Book, and he replied that he would act in accordance with God’s Messenger’s sunnah. He asked what he would do if he could find no guidance in God’s Messenger’s sunnah, and he replied that he would do his best to form an opinion and spare no pains. God’s Messenger then tapped him on the breast and said, “Praise be to God who has disposed His Messenger’s Messenger to something with which God’s Messenger is pleased!" Tirmidhi, Abu Dawud and Darimi transmitted it.