Is a person held accountable for their wrongdoings if they did not inquire about their prohibition or permissibility? Is one excused for their ignorance of matters they did not research? Is it obligatory for one to advise others with what they know, even if they do not act upon it? And is it permissible for them to conceal knowledge in this situation?

It is prescribed for one who learns something to teach it to others, even if he himself does not practice it. It is not permissible for him to conceal knowledge that must be taught due to his not acting upon it. Rather, he must teach good and act upon it, and his words must match his deeds, as Shu'ayb (peace be upon him) said: "And I do not wish to be at variance with you in that which I forbid you." And whoever does not act upon what he knows has exposed himself to danger, because of Allah's saying: "O you who have believed, why do you say what you do not do?", and the Prophet (peace and blessings be upon him) said about the man who is thrown into Hell: "I used to enjoin good, but I did not do it, and I used to forbid evil, but I committed it." Despite this warning, a Muslim must enjoin good and forbid evil, for justice is not a condition for it, as Al-Saffarini and Al-Qurtubi said, because if enjoining and forbidding were only to be done by one who is free of blemish, then enjoining and forbidding would be abandoned entirely.