All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
The station of prophethood is the highest of stations, and no other station can match it or come close to its rank. In the sight of Allah, our Prophet Mohammad (peace be upon him) is the leader of all messengers and the best of all creation. This is whether we say he died as a result of poison and thus attained martyrdom, or not
Many scholars have concluded that our Prophet Mohammad (peace be upon him) died as a martyr because his passing was due to the effects of the poison he consumed at Khaybar. This poison did not immediately affect him by Allah's preservation so that he could fulfill his mission and deliver the trust. However, it took its toll when his time came, allowing Allah to combine for His Prophet the stations of prophethood and martyrdom, thus magnifying his status and honor in the sight of Allah.
They have supported this conclusion with evidence such as:
Narrated `Aisha: The Prophet (PBUH) in his ailment in which he died, used to say, "O `Aisha! I still feel the pain caused by the food I ate at Khaibar, and at this time, I feel as if my aorta is being cut from that poison." {Transmitted by Bukhari}.
Another evidence is the hadith narrated by Al-Hakim from Umm Mubashir (may Allah be pleased with her). She said to the Prophet (PBUH) during the sickness of which he died: What do you think about your illness, Messenger of Allah (PBUH)? I do not think about the illness of my son except the poisoned sheep of which he had eaten with you at Khaybar. The Prophet (PBUH) said: And I do not think about my illness except that. This is the time when it cut off my aorta. Al-Hakim classified this narration as authentic according to the conditions of the two Sahihs (Bukhari & Muslim), but they did not report it. [Al-Mustadrak, Vol. 3/P. 242].
Among the narrations is what Ibn Mas'ud (may Allah be pleased with him) and others used to say: "He (the Prophet) died as a martyr from the poison." [Lata'if al-Ma'arif by Ibn Rajab, p. 106].
What happened to the Prophet Mohammad (peace be upon him) does not contradict the concept of infallibility. His death was not sudden, nor was it due to murder or assassination. Rather, his passing was natural due to the fever and headache resulting from the effects of the poisoned food he consumed at Khaybar. This poisoning did not affect him immediately, as he continued to lead armies, engage in major battles, achieve victories, negotiate with enemies, receive delegations, and live his daily life normally until he passed away and joined Allah the Almighty.
The fact that the Prophet Mohammad (peace be upon him) was poisoned does not contradict the verse in Surah Al-Ma'idah (5:67), "Allah will protect you from the people," because this verse specifically refers to protecting the Prophet from being killed. Allah protected the Prophet from the harm of that poison throughout his life. Ibn Battaal, may Allah have mercy on him, explained this by saying, "Allah protected him from the harm of the poison after informing him about the treachery through a miraculous sign that He showed him in the words of the goat`s arm that he was eating. Then Allah protected him from its harm throughout his life until the time of his passing when the poison overcame him, causing him pain. Allah willed for him martyrdom through that food." [Explanation of Sahih Bukhari, Vol. 5/P. 347].
In conclusion, the impact of the poison on the Prophet Mohammad (peace be upon him) was a means to elevate his status and increase his rank in the sight of Allah. Through this, he attained the station of martyrs in addition to his position as a prophet. And Allah the Almighty knows best.