An act of Sunnah or only desirable

A: All Praise is due to Allah Alone and peace and blessings be upon His Messenger, his family, and Companions.The authentic Sunnah of the Messenger of Allah (peace be upon him) indicates that it is Wajib (obligatory) to let the beard grow long and that it is Haram (prohibited) to shave or trim it. It is recorded in the Two Sahih (authentic) Books of Hadith (i.e. Al-Bukhari and Muslim) on the authority of Ibn `Umar (may Allah be pleased with them) that the Prophet (peace be upon him) said, "Trim the moustache and let the beard grow to differ from the Mushriks (those who associate others with Allah in His Divinity or worship)." It is recorded in Sahih Muslim on the authority of Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace be upon him) said, "Cut the moustache and let the beard grow to differ from the Magi." These two Hadith, and others that have the same meaning, clearly show the obligation of both letting a beard grow long and the prohibition of cutting or shaving it, as was mentioned above. Anyone who claims that letting the beard grow is Sunnah (a commendable act) and that anyone who grows one will be rewarded and those who do not will not be punished, are mistaken, as they have contradicted the Hadith Sahih (authentic). The basic ruling regarding commands [in the Prophet's Hadith. Trans.] is that they are Wajib and the prohibitions are Haram. It is therefore not permissible for anyone to hold an opinion that contradicts the apparent meaning of Hadith Sahih, unless there is supporting evidence to warrant otherwise. There is no such evidence in regard to the Hadith mentioned above.As for the Hadith that was related by Al-Tirmidhy on the authority of Abu Hurayrah (may Allah be pleased with him) that The Prophet (peace be upon him) used to remove some of the length and the width of his beard , this is a Batil (null and void) Hadith that is not known to have been authentically narrated from the Messenger of Allah (peace be upon him). Its Sanad (chain of narrators) includes a narrator who is accused of lying.Additionally, deriding beards and comparing them to pubic hair is a great Munkar (that which is unacceptable or disapproved of by Islamic law and Muslims of sound intellect), and obligates that (Part No. 5; Page No. 142) the person doing so be declared an apostate from Islam. This is because mocking anything that is indicated by the Book of Allah or the Sunnah of His Messenger Muhammad (peace be upon him) is considered an act of Kufr (disbelief) and Riddah (apostasy) from Islam, as Allah (Glorified and Exalted be He) says: Say: "Was it at Allâh (عز وجل), and His Ayât (proofs, evidence, verses, lessons, signs, revelations) and His Messenger (صلى الله عليه وسلم) that you were mocking?" Make no excuse; you disbelieved after you had believed. We ask Allah to grant us, you, and all Muslims, true guidance, success, and protection from misleading Fitnah (trial).May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.