Izar is defined in Arabic to be any lower garment tied to the waist covering the lower half of the body. It includes shalwar, pants, dhooti, pajamas, thawb, etc. In hadith the Prophet divided the length of the izar into four categories:
(1) The Sunna is upto half of the shins.
(2) The rukhsa (concession) is below half the shins till the ankles.
(3) The haraam and a kabira sin are letting it go below the ankles without pride.
(4) Even stronger in prohibition and punishment is dragging or trailing below the ankles out of pride
(1) Abu Hurairah (Radhiyallahu anhu) narrates: Rasulullah (sallallahu alayhi wasallam) said: “Whatever of the garment is below the ankles will be in the Fire (of Jahannum). (Bukhaari).
(2) Ibn Umar (Radhiyallahu anhu) narrates: “Verily the Nabi (sallallahu alayhi wasallam) said: Whoever hangs his garment in pride, Allah will not look at him (with mercy) on the day of Qiyamah.” (Bukhaari and Muslim)
(3) Abu Saeed al-Kudri (Radhiyallahu anhu) narrates “I heard Rasulullah (sallallahu alayhi wasallam) saying: The izaar of the Mu’min is halfway on the forelegs (i.e. midway between the knees and the ankles). There is no sin on him in that which is between it and the ankles. And, whatever is below this is in the Fire (of Jahannum). He (Rasulullah sallallahu alayhi wasallam) repeated this statement) three times. And, he said: Allah will not look (with mercy) at the person who hangs his izaar in pride.” (Abu Dawood and Ibn Maajah)
(4) Ibn Umar (radhiyallahu anhu) narrates: “I passed by Rasulullah (sallallahu alayhi wasallam) while my trousers were hanging (i.e. below the ankles). He then exclaimed: O Abdullah! Raise your izaar I then raised it (a bit). Then he (Rasulullah sallallahu alayhi wasallam) said: Raise it more! I then raised it more. Thereafter I was always conscious of it.” Some people asked: Until where (did you raise it)? He (Ibn Umar) said: Until midway of the foreleg.” (Muslim)
(5) Ubaid Bin Khaalid (radhiyallahu anhu) narrates: While I was walking in Madinah, (I heard) someone behind me say: “Raise your izaar! Verily it (raising the garment) is better for piety and preservation (of the garment).” I then looked behind and observed that it was Rasulullah (sallallahu alayhi wasallam). I then said: O Rasulullah! It is a simple (of inferior quality and price) garment. Rasulullah (sallallahu alayhi wasallam) commented: “What, is there not for you in me an example (to follow)?” When I looked (at Rasulullah’s garment), his izaar was midway on his forelegs.” (Tirmizi)
(6) Salmah Bin Akwa’ (radhiyallahu anhu) narrates: “Uthmaan (radhiyallahu anhu) would wear his trousers midway on his forelegs, and he would say: ‘So was the izaar of my Companion, i.e. Nabi (sallallahu alayhi wasallam). (Tirmizi)
(7) Huzaifah Bin Yamaan (radhiyallahu ahnu) narrates: Rasulullah (sallallahu alayhi wasallam) took hold of the flesh of my forleg (or of his forleg) and said: ‘This is the location for the izaar. If you are not satisfied (with this position), then a bit lower. And if you are still not satisfied, then know that the izaar has no right in the ankles.”(Tirmizi)
(8) The Prophet (Sallallaahu Álayhi Wasallam) saw a man with a long waist-shirt (Izar) and ordered him to have his izaar halfway up his shins; the man gave the excuse that he had a defect in his ankles, so the Prophet (Sallallaahu Álayhi Wasallam) said, “All of Allaah’s creation is handsome.” (sahih-Ahmad and again this shows the clothing can not go under the ankle even if it is not out of pride!)
(9) Abu Jurayy Jabir bin Sulaim was instructed by the Prophet: “Have your izar halfway down to your shin, if you can not do it, have it up to the ankles. Beware of hanging down the izar for it is makheela (pride), and Allaah does not like pride.” (Abu Daud, Tirmidhi who declared it hasan-sahih)
(10) A man was praying with his izar hanging down. The Messenger of Allaah said to him, “Go and perform wudu’.” He went and performed wudu’. He came back and the Prophet said, “Go and perform wudu’.” A man asked, “O Messenger of Allaah, what is the matter with you that you commanded him to perform wudu’ and then you kept silent?” He replied, “He was praying while hanging down his izar, and Allaah does not accept the prayer of a man who hangs down his izar.” (Abu Daud, Nisai, Tabarani. Nawawi declared its isnad to be sahih on the conditions of Imam Muslim and Dhahabi agreed with him in his “al-Kaba-ir.” Shams al-Haqq al-Adeemabadi declared it to he hasan)