Study of the divine Law is a collective duty, except where it is incumbent on the individual, e.g. everyone is obliged to find out what God has ordained for him and what He has proscribed for him. This is a duty for each individual. As reported in both Sahihs (Muslim and Bukhari), the Prophet, on him be peace, said: "When God wishes a man well He instructs him in knowledge of Religion." If God wishes a man well He will inevitably instruct him in Religion, so if a man is not versed in Religion God does not wish him well. Religion is what God sent His Messenger to convey. It is that which a man is bound to believe and practise.
Everyone owes general credence to Muhammad's, on him be peace, report and general obedience to his command; then if a report from him is confirmed it must be believed in particular, and if one receives a specific order to a certain effect one must obey it in particular.
"Public Duties in Islam" - Ibn Taymiya, p. 38