Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.

On this, I cannot do any better than citing here one of my earlier answers:

“Growing a beard is considered a great Sunnah of the Prophet (peace and blessings be upon him). It is also one of the great legacies inherited from all of the previous prophets and messengers of Allah. The Prophet (peace and blessings be upon him) ordered us: “Grow your beards and trim or clip the moustaches.” In light of such precedents, most of the past scholars and Imams go as far as declaring that growing a beard is obligatory on males.

What we stated above makes it clear that no Muslim should take the issue of the beard lightly. At the same time, we must also state categorically that one should not conclude from what has been said earlier that growing a beard in Islam has the same religious significance as that of the other prescribed rituals. This is definitely not the case. Thus it is important for us to recognize that we are not allowed to ostracize men who do not have beards nor are we to question their basic faith.

Since beard is undoubtedly a great Sunnah, every Muslim male should try to practice this Sunnah according to the best of his ability. Allah does not take us to task for what is beyond our power or ability. We are told to fear Allah as best as we can.

As for the size of the beard, there is nothing specific about it in the sources. How could the Prophet fail to mention it–if it had been an important matter? We are not allowed to be rigid on issues the Law-giver is silent about. The Prophet, peace be upon him, said, “That which Allah is silent about belongs to what He has excused–while saying this, the Prophet recited the verse, “your Lord is never forgetful’).

Almighty Allah knows best.