"Imam Abu Hanifa was (once) with A'mash, who asked him about something. Imam Abu Hanifa replied, 'My opinion in this matter is such-and-such.' Upon hearing this, A'mash asked as to how he had formed this (opinion). Imam Abu Hanifa said, 'You reported to us from Abu Salih who reported from Abu Hurayra; you reported to us from Abu Wa'il who reported from 'Abdullah; and you reported to us from Abu Ilyas who reported from Abu Mas'ud al-Ansari that the Messenger of Allah (saw) said such-and-such. You also reported the same to us from Abu Miljaz, who reported it from Hudhayfa, who from Abu'l-Zubayr, who from Jabir and Yazid al-Raqqashi, and they from Anas (ra).' A'mash explaimed, 'Enough! Enough! What took me a hundred days to narrate you repeated to me in just an instance. I was not aware that your practise was based on these hadiths.' Then he exclaimed, 'O group of jurists, your are the physicians, and we are merely the pharmacists; and you (addressing Abu Hanifa) are both.'" (Manaqib al-Imam 484) Taken from: http://www.muftisays.com/blog/Seifed...of-hadith.html