Is it permissible to wear a suit? Many people who wear suits leave their trousers beneath their ankles
Wa’alaykum as Salam wa rahmatullahi wa barakatuhu,
A Muslim should don such apparel that pious Ulama and other Allah-fearing servants of Allah adopt. That apparel would be the one that is closest to the Sunnah of Rasulullah (sallallahu alaihi wasallam) and that would be termed to be the correct Islamic dressing. For instance, the Qamees (Kurta) is a garb that has been donned for centuries by all our illustrious predecessors. The Qamees (Kurta) would be thus regarded as the correct Sunnah and Islamic dressing. It is mentioned in a Hadith of Sunan Abi Dawud,
“The most beloved clothes to the prophet (sallallahu alayhi wa sallam) was the Qamees.” (Sunan Abi Dawud, 4/76)
Wearing suits would result in emulating the dressing of the non-Muslim nations of the western world. We have been reproached in the Ahadith for emulating the dressing of other communities. The prophet (sallallahu alaihi wasallam) has warned in a Hadith:
“He who emulates another nation is (like) one of them.” (Sunan Abi Dawud, 4/78)
Furthermore, wearing the pants below the ankles is an action that is totally prohibited in Islam. The prophet (sallallahu alayhi wa sallam) said:
“The portion of the ankles that is covered by the lower garment (pants, etc) shall burn in the Fire of Jahannam.” (Sahih al-Bukhari and Sahih Muslim).
The Books of Ahadith are replete with many prohibitions of wearing the pants and other garments in such a way as to cover the ankles from above. For your research purposes, I refer you to Sahih al-Bukhari, Sahih Muslim and Sunan Abu Dawood, to name a few books. You will find these Ahadith under the chapters dealing with the etiquette of dressing.
And Allaah Ta’aala knows best
Ismail Moosa (Mufti)