The prophet pbuh said The meaning of the Hadith is trim the mustache and leave the beard. Let it grow. Today, when keeping a beard is not very fashionable, it is a sign of a proof that you love the prophet pbuh. You my dear Muslim men. Those of you who keep the beard.
It is a sign that you show that you belong to Muhammad pbuh and to his companions. This is why the word Aal. It means the people who belong to the Prophet pbuh.
Islamic Principles Website 