Growing a beard was considered normal and natural for a man at the time of the Messenger of Allah (saws), whether he was a believer or not. Even the enemies of Islam like Abu Jahl and Abu Lahb had beards! And because every man naturally grew a beard, it was not necessary for the Prophet (saws) to give an explicit command exhorting the believers to grow a beard.
The only specific saying of the Prophet (saws) regarding the keeping of beards arose when he saw that the pagans used to grow both their beards and their mustaches long; thus he (saws) said to the believers:
Ibn 'Umar related that the Messenger of Allah (saws) said: "Differ from the polytheists: let your beards (grow), and trim your moustache."
Related by al-Bukhari and Muslim.
It was only a couple of centuries ago, when the western culture and ideology became dominant over the world and muslim lands, that it became a fashion to be clean shaven. And as with any dominant culture, people are always ready to adopt its actions, whether they are of virtue, or of vice! But Islam has its own culture, and growing a beard is part of the Islamic culture.
The question is why should a believer, who professes to believe in Allah and the Last Day, and who professes to follow the Sunnah of the Messenger of Allah (saws), want to grow a beard?
The answer is simple. Today, you might have seen many youngsters copy the fashion of sport-stars, Hollywood-stars or anybody else whom they love. If you notice today, many hotHollywood stars and sport stars are sporting a "goatie" beard! And true to fashion, you see a lot of people around today who keep "goatie" beards!!! As Muslims, our role model should always be the Prophet (saws). We love to copy everything he did ... he had a beard, and if indeed, we want to follow the Messenger of Allah (saws), we should strive to grow a beard.
Allah says in the Holy Quran Chapter 33 Surah Ahzab verse 21:
There is indeed the best model for you in the Messenger of Allah, for every such person looks forward to Allah and the Last Day, and remember Allah much.
In another narration, the Prophet of Allah said in narrating a prophecy of times to come:
Sahih Al-Bukhari Hadith 9.651 Narrated by Abu Said Al Khudri
The Prophet (saws) said: “There will emerge from the East some people who will recite the Quran, but it will not exceed their throats, and who will go out of the deen of Islam as an arrow passes through the game. They will never come back to it unless the arrow comes back to the middle of the bow by itself (i.e. impossible!). The companions asked, "What will their signs be?". The Prophet (saws) said: "Their sign will be the habit of shaving off of their beards".
Thus the keeping of beards is an encouraged and preferred Sunnah of the Prophet (saws) and every muslim male must strive to keep a beard, if his model is indeed the Prophet of Allah (saws). He will get his due reward from Allah, Insha Allah, if he keeps the beard to follow the Sunnah of the Messenger of Allah (saws).
But if a believer does not want to sport a beard for whatever reason, the other believers should not make an issue out of it. What is important in Islam and in the Sight of Allah, is that one truly believes and does good righteous deeds. And when that happens, it is expected that the beard will follow soon after!
The beard is nothing more than a sign that the believer truly wants to follow a Sunnah of the Messenger of Allah (saws). There are many people who have long beards, but do deeds against the commands of Allah and His Messenger (saws). And there are many people who are amongst the best believers, but do not have beards! Allah will not decide the recipient of His Mercy and His Forgiveness from the appearance of the individual; but rather He will decide whether the person believed and did righteous deeds, as was commanded by Allah and His Messenger (saws).
Ref: the trimming of the moustache
Al-Muwatta Hadith 49.3
Yahya related from Malik from Said ibn Abi Said al-Maqburi from his father that Abu Hurayra said that the Messenger of Allah (saws), "There are five things from the ‘fitra’ (nature): cutting the nails, trimming the moustache, removing the hair from the armpit, shaving the pubic region and circumcision."
Al-Tirmidhi Hadith 4437 Narrated by Abdullah ibn Abbas
The Prophet (saws) used to clip or take something off his moustache, and Prophet Ibraheem, the ‘Khaleel’ (intimate friend) of the Compassionate One, used to do the same!
Al-Tirmidhi Hadith 4438 Narrated by Zayd ibn Arqam
Allah's Messenger (saws) said, "He who does not take something off his moustache is not one of us."
Sahih Al-Bukhari Hadith 7.780 Narrated by Nafi
Abdullah Ibn Umar said that the Prophet (saws) said, "Do the opposite of what the pagans do. Keep the beards and cut the moustaches short.". Ibn Umar used to cut his moustache so short that the whiteness of his skin (above the upper lip) was visible, and he used to cut (the hair) between his moustaches and his beard.
The Arabic term used for ‘shaving’ is ‘halaq’; while the term to cut or trim in Arabic is ‘Qass’ or ‘Ahfu’…..and in all the guidance regarding the moustache the term used in the hadith is either ‘Qass’ or ‘Ahfu’ (meaning cut or trim) and never ‘Halaq’ (shave).
The scholars and jurists in Islam are almost unanimous in their opinion that the Sunnah is to cut or trim the moustache, rather than shave it completely.
Whatever written of Truth and benefit is only due to Allah’s Assistance and Guidance, and whatever of error is of me alone. Allah Alone Knows Best and He is the Only Source of Strength.
Your brother and well wisher in Islam,