Is a Muslim sinful if he follows an opinion that is considered disliked by some and forbidden by the majority, such as shaving the beard, while being convinced of its correctness? And is persistence in committing a disliked act considered a sin over time?

If a Muslim is not qualified for ijtihad, he may follow a scholar whose knowledge and piety he trusts, according to the words of the Almighty: "So ask the people of the message if you do not know." If the jurists differ, the follower may choose between the various opinions of the muftis, or act upon a type of preference, while being careful not to follow dispensations; because persistence in committing a disliked act incurs sin upon its doer, and a minor sin becomes a major one through persistence.

It is recommended to grow the beard, as it is a Prophetic Sunnah, and because the straight guidance restrains a person from many forbidden acts.