On his father's authority, said that his grandfather reported the Messenger of Allah ﷺ said: Anyone who practises medicine when he is not known as a practitioner will be held responsible. Abu Dawud said: This has been transmitted by al-Walid alone. We do not know whether it is sound or not.
أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ مَنْ تَطَبَّبَ وَلاَ يُعْلَمُ مِنْهُ طِبٌّ فَهُوَ ضَامِنٌ قَالَ نَصْرٌ قَالَ حَدَّثَنِي ابْنُ جُرَيْجٍ