"O you who believe! Follow Allah; follow the Messenger and those of authority (Amr) amongst you." (Surah Al-Nisaa: 59)

"SO, ask the people (having the knowledge) of the Message, if you do not know". (16:43)(21 :7)

"Do you know all the various laws of Deen? Are you capable of extracting and deriving the laws pertaining to wudhu, salaah, zakaah, etc. directly from the Qur'an and Hadith? Do you know which Hadith has abrogated another? Do you have the ability to reconcile between the various Ahadith which apparently contradict each other? Do you know which verses of the Qur'an are general in their application and which verses are qualified by other texts?"

If not then the following aayah applies "Ask those of knowledge if you do not know." (16:43 & 21:7)
Hence due to not have enough knowledge in these fields we have opted to follow one of those great people who had attained that distinguished mastery in this field, among whom is a Tabiee, Imaam Abu Hanifa (R.A.).