The incident of the emmisary of Kis'ra has already been mentioned briefly. Maulana Meeruti (may Allah's mercy be upon him) writes in detail, when Abdullah ibn Huzafah Radiallahu anhu presented Rasulullah's Salallahu ‘Alayhi Wasalam letter to Khusru Parwez, the king of Iran (Kis'ra), he tore it up in anger and said : 'An ordinary low subject of my Empire writes to me, and has his own name written before mine'.
He than ordered Baazaan, who was his governer of main, and under whose governership they considered all the Arab lands to be, to have this person - Rasulullah Salallahu ‘Alayhi Wasalam arrested and brought to his court. Complying, Baazaan dispatched a group of army officers under the leadership of Khar Khusru. To study and investigate the conditions of Muhammad Salallahu ‘Alayhi Wasalam an additional officer by the name of Baanuyah accompanied them.
When these two officers appeared in the presence of Rasulullah Salallahu ‘Alayhi Wasalam, they began to tremble and shiver due to the overbearing spiritual character of Nabi Salallahu ‘Alayhi Wasalam. These people were fire-worshipping Parsees, and their beards were shaven, they had overgrown moustaches, and they used to call Kis'ra 'Lord'. Rasulullah Salallahu ‘Alayhi Wasalam was displeased on seeing their faces, and the first question he asked them was, “Who has told you to make your appearance like this ? They replied : 'Our Lord, Kis'ra did.”
Rasulullah Salallahu ‘Alayhi Wasalam said : 'My Lord has commanded me to lengthen the beard, and cut the moustache'. The point that has to be understood is that Rasulullah Salallahu ‘Alayhi Wasalam was upset and displeased by this appearance of these non-Muslim representives. The late Maulana Yousuf Kandahlawi (may Allah enlighten his resting place) has related this incident from a number of sources in his book 'Hayaat us Sahabaa'. Muslims should seriously think that after death the very first stage will be to face Rasulullah Salallahu ‘Alayhi Wasalam. How displeased and disappointed will he be to see that face which is not according to his teaching or his Sunnah, when every Muslim hopes for his intercession in the Hereafter.
Thereafter Maulana Meeruti (may Allah bestow mercy upon him) relates the story of Mirza Qateel, Learning of his sufic talks an Irani was impressed and became an admirer. To meet him he eagerly undertook a special journey. When he reached the Mirza, he found him shaving his beard. He was astounded and said : 'Aaghaa ! (Sir), you are shaving your beard ! ' The Mirza replied : 'Yes. I am shaving my own hair, I am not shaving anyones heart', thus referring to the sufi concept that you could do what you please with your self, but you should not hurt the hearts of the creation of Allah. The Irani without hesitation exclaimed : “O ! You definitely are shaving the heart of Rasulullah Salallahu ‘Alayhi Wasalam 'What do you mean that you are not hurting the heart of any person; when you are piercing the heart of Rasulullah Salallahu ‘Alayhi Wasalam.”
On hearing this the Mirza went into a trance, and dropped unconscious. When he regained his senses he recited the following verse:
'May Allah reward you, You have opened my eyes;
And have made a personal union, with the king of all souls'.
Thus if there is no intention of pleasing Allah's beloved Rasul Salallahu ‘Alayhi Wasalam, by doing what he taught; for Allah's sake do not hurt his heart, Rasulullah Salallahu ‘Alayhi Wasalam is Allah's most beloved, and to displease him is to displease Allah. Rasulullah Salallahu ‘Alayhi Wasalam has said 'Whoever displeases me has displeased Allah.' If Rasulullah Salallahu ‘Alayhi Wasalam is hurt by non-Muslims shaving their beards and having overgrown moustaches, how much more disturbed and displeased will he be with those who claim to be his followers, and yet commit this sinful act.
Extracted from "The Beard of a Muslim and its Importance" by Hazrat Sheikh Zakariyya Rahmatullah alayhi