What is the wisdom behind keeping a beard?

I have got a beard but I was recently asked by a non-Muslim as to why Muslims have to keep a beard. I accept that we have to keep a beard because the prophet (saw) kept it and all prophets and sahabahs kept it and prophet Muhammed also told the ummah to keep it, but why, what's the wisdom behind it?

In the Name of Allah, Most Merciful and Compassionate

May Allah's peace and blessings be upon His Messenger Muhammad, his folk, companions, and followers

The fundamental reason is, as you mentioned, that the Messenger of Allah (peace and blessings be upon him) commanded Muslim men to keep their beards. Allah Most High has commanded us to obey the Messenger of Allah (peace and blessings be upon him), telling us that, "Whoever obeys the Messenger has indeed obeyed Allah." [Qur'an] Allah Most High has also told us that, "If you obey him, you shall be guided." [Qur'an]

Following the example of the Messenger of Allah (peace and blessings be upon him) is also an expression of love for Allah and for His Messenger (Allah bless him and give him peace), and is a means to attaining unto Divine Love, for Allah Most High says to the Prophet (Allah bless him and give him peace), "Say: If you love Allah, then follow me, and Allah will love you." [Qur'an]

The Messenger of Allah (peace and blessings be upon him) told us that keeping the beard is from the fitra, the natural disposition of humans. When this natural disposition--like other outward aspects of appearance--is maintained in accordance with Divine Guidance, it is a manifestation of outward perfection from which inward spiritual meanings of drawing close to the Divine through faith, devotion, thankfulness, the joy of servitude, and pure love result.

And Allah alone gives success.

Wassalam,

Faraz Rabbani