This thread is not intended to attack on anyone’s beliefs or ideals, but to only learn the perspective of people from whom it is asked. IT is just a doubt which needs to be cleared. Please do not de-rail the thread with useless offensive comments and attacks on any particular group or person.
There are hadiths mentioned on the site al-islam.com and many other sites from authentic Hadith books regarding trimming of mustaches as long mustaches makes the drinking water makrooh and unhealthy (also scientifically proved).
'Abdullah bin 'Umar, may Allah be pleased with them, said:
The Messenger of Allah (may peace be upon him) said: Trim closely the mustache, and let the beard grow. Hadith number in Sahih Muslim [Arabic only]: 380
Also, as mentioned by a lot of muslim scholars (and scientifically proved) the mustache gives off a certain secretion which is not healthy, and if it were to go into food and water, then it would be unhealthy. Therefore, we should trim the mustache. Also it is mentioned that touching of mustache with water makes it makrooh for drinking.
Sahih Al-Bukhari Volume 7, Book 72, Hadith # 780:
It is narrated about Ibn Umar (Radhiallaahu Án) “Ibn Umar used to cut his moustache so short that the whiteness of his skin (above the upper lip) was visible”
Imaam Malik’s Muwatta Book 49, Hadith # 49.3.4:
Yahya related to me from Malik from Yahya ibn Said that Said ibn al-Musayyub said, "Ibrahim, may Allah bless him and grant him peace, was the first to give hospitality to the guest and the first person to be circumcised and the first person to trim the moustache and the first person to see grey hair. He said, ‘O Lord! What is this?’ Allah the Blessed, the Exalted, said, ‘It is dignity, Ibrahim.’ He said, ‘Lord, increase me in dignity!’ "
Yahya said that he had heard Malik say, “One takes from the moustache until the edge of the lip appears, that is the rim. One does not cut if off completely so that one mutilates oneself.”
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Sahih Al-Bukhari Volume 7, Book 72, Hadith # 776:*
Narrated Ibn Umar: The Rasulullah (Sallallaahu Álayhi Wasallam) said, “To get the moustaches cut 'short is characteristic of the Fitra.”
And there are so many hadiths on trimming of mustaches.
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With all due respect we see something else in the photographs of Mirza Sahab.