Tirmidhi

Hadith Commentary:
When revelation would descend upon the Noble Messenger (sallallahu alayhi wa sallam), his condition would change; even in severe cold, he would perspire profusely and his blessed body would become heavy.
The narrator has described this very state here.
In the verse, with these words, the blind, the sick, and the disabled have been exempted from the obligation of jihad.
It is true: ﴿لَا یُکَلّفُ اللہُ نَفسنا اِلا وُسْعَھَا﴾ (al-Baqarah: 286)
The divine commands are only necessary to fulfill within the limits of human capacity and strength.

Hadith Commentary:
➊
From this verse, it is understood that jihad is not an individual obligation (fard ‘ayn) but rather a collective obligation (fard kifayah), because in society there are many individuals who are elderly, weak, frail, blind, lame, and ill, etc., who simply cannot go out for jihad. Furthermore, some people must necessarily remain behind for the internal defense of the country, to protect the homes of the mujahideen, to look after their families, and also so that they may provide timely assistance to the mujahideen—whether this pertains to supplies and provisions or manpower. Then, some people are also necessary for the care of the wounded.

➋
It is also explicitly established from the noble verse that those believers who do not participate in the battlefield without a physical excuse—Allah Ta‘ala has also promised them goodness and Paradise. However, if jihad were in every case an individual obligation (fard ‘ayn), then why would Allah promise goodness to those who remain behind from jihad? Accordingly, Hafiz Ibn Kathir rahimahullah writes:
“This verse is evidence that jihad is not an individual obligation (fard ‘ayn) but rather a collective obligation (fard kifayah).” (Tafsir Ibn Kathir: 1/821)

➌
Although Allah Ta‘ala accepted the excuse of Abdullah bin Umm Maktum radi Allahu anhu, despite this concession, his zeal for jihad was so great that he participated in many expeditions (ghazawat) even by enduring hardship.
The details of the circumstances in which jihad becomes an individual obligation (fard ‘ayn) have already been mentioned previously.

Benefits and Issues:
➊
If a sick person, a blind person, a disabled person, or someone with another valid Shar‘i excuse stays behind from jihad, it is permissible. However, when there is a command for general mobilization (nafir ‘aam), then staying behind without an excuse is in no way allowed.

➋
At the time of the descent of revelation, an extreme burden would be placed upon the Messenger of Allah (sallallahu alayhi wa sallam). Even in severe cold, sweat would appear on him (sallallahu alayhi wa sallam). And if he (sallallahu alayhi wa sallam) was on a she-camel, it too would kneel down and be unable to move.

➌
Whatever portion of the Noble Qur’an was revealed, the Noble Prophet (sallallahu alayhi wa sallam) would have it written down. However, in the beginning, there was no general permission to write down hadiths. Except for a few Companions (radi Allahu anhum ajma‘een), most of the documents that he (sallallahu alayhi wa sallam) had written were specifically commissioned.

(1) To risk one's life, or even to sacrifice it, purely for the pleasure of Allah Ta'ala is no ordinary virtue. This is why the mujahideen (those who strive in Allah's cause) possess much greater merit over other righteous people. However, if a person who is excused (ma‘dhur) holds the intention for jihad, he too will receive the reward of jihad.

(2) Hazrat Ibn Umm Maktum radi Allahu anhu was blind. In the Arabic language, "maktum" refers to a blind person. There is a difference of opinion regarding his name. Most researchers have stated it as Abdullah, while some have said Amr as well. And Allah knows best.

(3) There is no objection to the words ﴿غَيْرُ أُولِي الضَّرَرِ﴾ (an-Nasa'i: 4:95) being revealed afterwards, because even if these words were not present, the concession for the excused person is established by the legal evidences (shar‘i adillah), and receiving the reward for intention is also an unequivocal matter. However, due to the importance of jihad, the need for clarification was felt, so clarification was provided.