If a layperson does his best to ask a scholar that he trusts to give him the Islamic ruling on a particular issue, then he has done what Allah has commanded him to do, and this suffices him in this life and the next. The layperson is not responsible for knowing the evidence of his Mufti (or Madhhab), nor what other scholars have said. So long as he has taken the advice of someone who is qualified in Fiqh and Ifta, and he is sincere in seeking the Islamic ruling, then that is enough. This is generally agreed upon by the scholars as stated by Shaykhu-l Islam Ibn Qudamah (r).
[See: al-Rawdhah by Imam Ibn Qudamah (r)]5706total visits,4visits today