There are many sources in support of the Muslims affinity for beards. Though the Quran does not contain anything in this regard, most Muslim clerics believe that wearing bead is a way of showing total obedience to messenger of Allah, the prophet, and a part of Sunnah. Aka Sira, the biography of the prophet contains an account of the prophet ordering his followers to grow beards as a way of distinguishing themselves from the Persians/Zoroastrian. Growing beard has sometimes been mentioned as an important aspect of personal hygiene, known as, Fitra as contained in the Hadith. Some minor group of Muslim scholars believe that it is mandatory for every Muslim to grow beard as proclaimed by Ibn Taymiyyah, the 14th scholar. The modern Salafi movement has further reaffirmed this.
In the Quran, Allah is totally silent when it comes to the issues of Muslims wearing beads. This is the reason why most Muslim scholars find it hard to make beard growing mandatory for all male Muslims in spite of the prophet's love for beards.