Bukhari

Understanding of the Hadith:
In another narration, along with wealth, religion, family, and life are also mentioned. [صحيح جامع الصغير : 6445، نسائي : 4095، ترمذي : 1421]
From this it is understood that if someone attacks another’s wealth, life, or honor, then it is permissible to fight against him, and if, during this defense, the one defending himself is killed, he is a martyr (shaheed). And if the attacker is killed, then his blood is wasted (i.e., there is no liability for it); neither will there be any sin upon the killer, nor will he be required to pay retribution (qisas) or blood money (diyah).

Hadith Commentary:

Because he is oppressed. In the narration of al-Nasa’i, it is stated that Paradise is for him, and in the narration of al-Tirmidhi, it is further mentioned: “And whoever is killed while protecting his life, and whoever is killed while protecting his family, all of them are martyrs (shuhada).”

In the present times, throughout the world, the hundreds of Muslims who are being unjustly killed—all of them, according to this hadith, are included among the martyrs, because they are being killed solely for the crime of being Muslim. Indeed, to Allah we belong and to Him we shall return (inna lillahi wa inna ilayhi raji‘un).

Hadith Commentary:
The purpose of Imam Bukhari rahimahullah is that a person should defend himself and his wealth, because if he is killed, he attains the rank of martyrdom (shahadah), and if he kills (the aggressor), then neither blood money (diyah) nor retribution (qisas) is due upon him. Thus, it is mentioned in the hadith that a man came to the Messenger of Allah sallallahu alayhi wa sallam and said:

O Messenger of Allah! If a thief wants to take my wealth from me, what should I do? He (the Prophet) said:
"Do not give him your wealth."
He said:
What if he wants to kill me? He said:
"Then fight him."
He said:
What if he kills me? He said:
"Then you are a martyr."
He said:
What if I kill him? He said:
"Then he will be in the Fire."
(Sahih Muslim, Al-Iman, Hadith: 360(140))

The aforementioned hadith is mentioned in the Book of Injustices (Kitab al-Mazalim) for the reason that if someone wants to seize another's wealth, he may defend his wealth, even if he himself is killed or even if he kills (the aggressor).

And Allah knows best.

Hadith Commentary:
Benefits and Issues:
Anbasah bin Abi Sufyan (radi Allahu anhu)
wanted to forcibly make a water passage through the garden of Abdullah bin Amr (radi Allahu anhu),
therefore Abdullah (radi Allahu anhu) became ready to fight in order to protect his garden.

Explanation:

1:
The meaning is that if someone wants to unjustly take another person's wealth, then regardless of whether the wealth is little or much, the oppressed person has the right to defend his property. While defending, if the usurper is killed, then nothing—neither retribution (qisas) nor blood money (diyah)—is due upon the defender. And if the defender is killed, then he is a martyr (shaheed).

Imam Nasa'i rahimahullah's intention is that this narration is authentic through the chain of 'Abdullah bin Hasan from 'Ikrimah, as Sa'ir bin Khums has narrated it, and not through the chain of 'Abdullah bin Hasan from Ibrahim bin Muhammad as Sufyan al-Thawri has narrated it. However, for the Imam rahimahullah to call Sufyan's hadith an error is questionable, because al-Thawri is trustworthy (thiqah) and a memorizer (hafiz), and furthermore, he is not alone in this; rather, 'Abd al-'Aziz bin Mutalib has also followed him in this narration. Imam Tirmidhi rahimahullah has also narrated this narration and called it hasan (good). Thus, it appears that 'Abdullah bin Hasan has two teachers in this narration: 'Ikrimah and Ibrahim bin Muhammad. And the narration is authentic through both routes. For details, see: (Dhakheerat al-‘Uqba, Sharh Sunan al-Nasa’i: 32/73)

See, Hadith: 4089.

“He is a martyr”—that is, his forgiveness will also be granted like that of a martyr. He will receive a great reward because he was killed unjustly. A martyr is also killed unjustly. However, the rulings specific to one who is martyred in the path of Allah (shahid fi sabilillah) will not apply to him. For example: he will be given a ritual bath (ghusl) like an ordinary deceased person, and his funeral prayer will be performed. The same ruling applies to those who are called martyrs outside the battlefield. Umar radi Allahu anhu was martyred unjustly, yet he was given a ritual bath and his funeral prayer was performed. The same was the case with Ali and Uthman radi Allahu anhuma.