Sheikh Salman al-Oadah
You have the right to follow a certain school of thought such as the Malikî, Shafi`î, Hanafî, Hanbalî, Zâhirî, or Awza`î school. But neither you nor anyone else may follow one school in an issue where it is clearly established that the evidence points to the contrary.
Allah created us to worship Him and follow His Messenger (peace be upon him). Allah says: “Obey Allah and obey the Messenger”
We, as servants, will be asked on the Day of Judgment “What was the answer you gave to the Messengers?” [Sûrah al-Qasas: 65].
We are commanded to follow the revelation sent to Prophet Muhammad (peace be upon him). Allah says: “Follow (O men) the revelation given unto you from your Lord.” [Sûrah al-A`râf : 3]
The founders of all the schools of law used to tell their students not follow them in this or that but to take from the same source they have taken from and to follow the evidence. Those prominent Imams all had famous sayings related from them in this regard.
Therefore, whoever came to know a true Sunnah with certainty is forbidden to disregard it in deference to the saying of the scholar whom he chooses to follow.
Ibn `Abd al-Barr related the consensus of the scholars on this point.
This is a clear matter. However, for a common person who cannot distinguish between texts and evidences. it is perfectly alright for him to copy a scholar whom he trusts, and fear Allah as much as possible.
Source: Islam Today