Is it obligatory to rub the light beard and thick mustache with water during ablution, or is it sufficient to wash the face?

There is no difference between the ablution for a fard (obligatory) prayer and a nafl (supererogatory) prayer in ruling or manner. Combing through the beard is obligatory if it is sparse. If it is thick, washing its surface is sufficient. As for the mustache and eyebrows, Shafi'i jurists held that it is obligatory to make water reach the skin beneath them due to their rare thickness and the lack of difficulty in combing through them. However, the majority of scholars believe that it is not obligatory to comb through thick mustache hair, and washing its surface is sufficient. If it is sparse, the Hanbalis have explicitly stated the obligation of making water reach the skin.