How sound is the Hadith: "Let alone the beards and trim the moustaches," and what is the correct interpretation of the meaning of "let alone" mentioned therein? Does it mean to take from the beard and not leave it?

"Ifa" (letting grow) the beard is a Sunnah command, and its meaning is to lengthen and leave it, not to remove it. This is what the commentators of Hadith have agreed upon, and it is confirmed by other narrations such as "waffirū" (lengthen), "awfū" (make full), and "arkhū" (let hang down). No scholar has ever said that letting grow the beard means trimming it; rather, they stipulated leaving it. Letting grow the beard is among the characteristics of the fitra (primordial nature), and it is in opposition to the Majūs and the People of the Book who used to trim their beards. Scholars have agreed that "al-ifā'" means to let it grow fully, but many of them deemed it permissible to take from what exceeds a fistful or what disfigures the appearance, and this is what was narrated from Ibn Umar, may Allah be pleased with him.