Did Muhammad die within a year of his own proposed mubahala, the death of the party lying?

The argument sounds forceful only if a proposed mubahala is treated as an actual mubahala. In the Najran episode, the mutual curse was not performed, so the later death of the Prophet (PBUH) cannot be used as the result of it.

The strongest version of the case

The objection says: the Quran invited the Christians of Najran to a mubahala, meaning each side would call Allah's curse on the liar. Some Muslim writers, including Ibn Hajar, mention that those who enter such a curse do not remain unharmed beyond a year. Since al-Tabari and Ibn al-Jawzi place the Najran delegation around 631 CE, and the Prophet (PBUH) died in 632 CE after a painful illness, the objector argues that Islam's own test condemned him.

That is the argument at its strongest. Its weakness is that it quietly changes "he challenged them" into "they all performed it."

What the Quranic challenge required

"Then whoever argues with you about it after the knowledge that has come to you, say: Come, let us call our sons and your sons, our women and your women, ourselves and yourselves, then let us pray earnestly and place the curse of Allah upon the liars."

Quran 3:61

The verse describes a mutual act: both sides come, both sides invoke Allah, and the curse is placed upon the liar. The well-known reports say the Prophet (PBUH) came with Ali, Fatimah, Hasan, and Husayn, but the Najran Christians did not proceed with the mubahala. They chose a settlement instead.

When this verse was revealed, the Messenger of Allah (PBUH) called Ali, Fatimah, Hasan, and Husayn and said, "O Allah, these are my family."

Sahih Muslim

So the Islamic narrative is not: "A mubahala occurred, then we look for who died." It is: "A mubahala was offered, the other party refused, and a treaty followed." A refused oath is not an oath.

The "within a year" claim is not a Quranic rule

Ibn Hajar's statement about the effect of mubahala is best read as a reported observation about an actual mubahala, not as a new verse, not as a hadith establishing a universal legal test, and certainly not as something triggered by a proposal that was declined.

The dating also does less work than the objection suggests. Saying "631 to 632 CE" is too rough. The delegation is commonly placed in the Year of Delegations, 9 AH, while the Prophet (PBUH) died in Rabi al-Awwal 11 AH. Depending on the exact month assumed, the neat "within one year" framing is not established. But even if it were within a year, the central problem remains: the mubahala was not performed.

Death itself was never the sign of being cursed

The Quran plainly teaches that the Prophet (PBUH), like all messengers before him, would die. His death cannot by itself be turned into evidence of divine rejection.

"Muhammad is no more than a messenger. Messengers have passed away before him. So if he dies or is killed, will you turn back on your heels?"

Quran 3:144

The claim about his family also fails. The very people named in the mubahala reports did not "perish terribly" within a year. Ali lived for decades. Hasan and Husayn lived for decades. Fatimah died some months after him, and her death was not a mubahala judgment. The later tragedies of the Prophet's (PBUH) household are real and painful, but they cannot be retrofitted into a curse from an event that never took place.

So the objection establishes that the Quran issued a serious challenge and that Muslim sources treated mubahala with gravity. It does not establish that the Najran mubahala occurred, that Ibn Hajar supplied a binding criterion for this case, or that the Prophet's (PBUH) death was the death of the lying party.