The Quran gives Muslims a sign to know whether Muhammad was a liar and forger who made up revelations, and passed them off as coming from the true God:

And if he (Muhammad) had forged a false saying concerning Us (Allah), We surely should have seized him by his right hand (or with power and might), And then certainly should have cut off his life artery (Aorta [al-wateena]), And none of you could withhold Us from (punishing) him. S. 69:44-46 Hilali-Khan

According to this passage, Allah would cut off Muhammad’s aorta if he were to make up sayings and attribute them to God. The manner of death conveys the notion of Muhammad dying an excruciatingly painful death as a way of shaming and humiliating him for being a false prophet.

Shockingly, this is exactly how Muhammad died according to the supposed authentic Islamic narrations!

64 Military Expeditions led by the Prophet (Al-Maghaazi)

(83) Chapter: The sickness of the Prophet and his death

Narrated `Aisha:

The Prophet 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 (abhari) is being cut from that poison."

Reference: Sahih al-Bukhari 4428

In-book reference: Book 64, Hadith 450

USC-MSA web (English) reference: Vol. 5, Book 59, Hadith 713 (Sunnah.com: https://sunnah.com/bukhari:4428)

This means that Christ caused Muhammad to die the exact way the Quran says he would die if he was a false prophet. Christ brought upon Muhammad the very painful and shameful death, which the Quran says Muhammad would undergo in order to expose him as an imposter, a fraud, and an antichrist. The risen Jesus did this in order to convince Muslims to turn away from this false prophet and turn to Christ, since he is their only hope of salvation and wants to save them all.⁽¹⁾

Seeing how embarrassing this to Muhammad’s credibility, Muslims have tried to deny that his extremely painful and miserable death exposes him as a false prophet. One of the ways they’ve tried to do this is by claiming that the Quran and hadith use two different Arabic words. The Muslim scripture employs the term wateen, whereas the hadith has the word abhar instead. They think that this somehow disproves the fact of Muhammad dying the death of an accursed, rejected prophet solely because the exact same term isn’t used.

The problem with this response is that it overlooks the fact that al-wateen (الْوَتِينَ) and abhar (أَبْهَر) are actually synonyms that mean basically the same thing, just as any Arabic dictionary confirms. Note, for instance, what the following online dictionary states. All emphasis is mine:

وتين - Wiktionary, the free dictionary 

Etymology

Since the aorta supplies the cardiovascular system blood, perhaps a trace of Proto-Semitic *watan- (“to give”) put forward by a minority as the actual base verb “to give” which نَتَنَ (natana, “to stink”) derives from. وَتَنَ (watana) supposedly means “to be inexhaustible, to perpetual” of sources flowing without cease, paralleling like-patterned وَرِيد (warīd, “vein”) being related to وِرْد (wird, “watering-hole”).

Pronunciation

·       IPA^(key): /wa.tiːn/

Noun

وَتِين • (watīn) m (plural وُتُن (wutun) or أَوْتِنَة (awtina))

1.     (anatomy) aorta

Synonyms: أَبْهَر (abhar), أَوُرْطَى (awurṭā) 

أبهر 

Pronunciation

·       IPA^(key): /ab.har/

Noun

أَبْهَر • (ʔabhar) m

1.     (anatomy) aorta 

Synonyms: وَتِين (watīn), أَوُرْطَى (awurṭā)

أورطى

Etymology

Borrowed from Ancient Greek ἀορτή (aortḗ).

Pronunciation

·       IPA^(key): /a.wur.tˤaː/

Noun

أَوُرْطَى • (awurṭā) m

1.     (anatomy) aorta

Synonyms: أَبْهَر (abhar), وَتِين (watīn)

Therefore, the excuse that the Quran and hadith do not employ the exact wording fails to address the problem of Muhammad dying a shameful, humiliating, painful death at the hands of Jewess who gave him poisoned sheep to eat in order to expose and get rid of him as a false prophet:

41 Types of Blood-Wit (Kitab Al-Diyat)

(1649) Chapter: If A Person Gives A Man Poison To Drink Or Eat, And He Dies, Is He Subject To Retaliation?

Narrated Abu Hurairah:

The Messenger of Allah would accept a present, but would not accept alms (sadaqah). And Wahb bin Baqiyyah narrated to us, elsewhere, from Khalid, from Muhammad ibn Amr said on the authority of AbuSalamah, and he did not mention the name of Abu Hurairah: The Messenger of Allah used to accept presents but not alms (sadaqah).

This version adds: So a Jewess presented him at Khaybar with a roasted sheep which she had poisoned. The Messenger of Allah ate of it and the people also ate.

He then said: Take away your hands (from the food), for it has informed me that it is poisoned. Bishr ibn al-Bara' ibn Ma'rur al-Ansari died.

So he (the Prophet) sent for the Jewess (and said to her): What motivated you to do the work you have done?

She said: If you were a prophet, it would not harm you; but if you were a king, I should rid the people of you. The Messenger of Allah then ordered regarding her and she was killed. He then said about the pain of which he died: I continued to feel pain from the morsel which I had eaten at Khaybar. This is the time when it has cut off my aorta.

Grade:  Hasan Sahih (Al-Albani)

Reference: Sunan Abi Dawud 4512

In-book reference: Book 41, Hadith 19

English translation: Book 40, Hadith 4497 (Sunnah.com: https://sunnah.com/abudawud:4512)

41 Types of Blood-Wit (Kitab Al-Diyat)

(1649) Chapter: If A Person Gives A Man Poison To Drink Or Eat, And He Dies, Is He Subject To Retaliation?

Narrated Ibn Ka'b b. Malik:

On the authority of his father: Umm Mubashshir said to the Prophet during the sickness of which he died: What do you think about your illness, Messenger of Allah? 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 said: And I do not think about my illness except that this is the time when it cut off my aorta.

Abu Dawud said: Sometime 'Abd al-Razzaq transmitted this tradition, omitting the link of the Companion, from Ma'mar, from al-Zuhri, from the Prophet, and sometimes he transmitted it from al-Zuhri from 'Abd al-Rahman b. Ka'b b. Malik, 'Abd al-Rahman mentioned that Ma'mar sometimes transmitted the tradition in a mursal form (omitting the link of the Companion), and they recorded it. And all this is correct with us. 'Abd al-Razzaq said: When Ibn al-Mubarak came to Ma'mar, he transmitted the traditions in a musnad form (with a perfect chain) which he transmitted as mauquf traditions (statements of the Companions and not of the Prophet).

Grade:  Sahih in chain (Al-Albani)  

Reference: Sunan Abi Dawud 4513

In-book reference: Book 41, Hadith 20

English translation: Book 40, Hadith 4499 (Sunnah.com: https://sunnah.com/abudawud:4513)

29 Excellent Qualities and Description of the Prophet

(9c) Chapter: The Migration of his Companions from Makka and his Passing - Section 3

She told that in the illness from which he died God's messenger I was saying, ```A'isha, I still feel the pain from the food I ate at Khaibar, and this is the time when I feel my aorta being cut because of that 'poison." Bukhari transmitted it.

Reference: Mishkat al-Masabih 5965

In-book reference: Book 29, Hadith 221 (Sunnah.com:  https://sunnah.com/mishkat:5965)

75 Patients

(2) Chapter: The severity of disease

Narrated Aisha: I never saw anybody suffering so much from sickness as Allah's Messenger.

Reference: Sahih al-Bukhari 5646 

In-book reference: Book 75, Hadith 6 

USC-MSA web (English) reference: Vol. 7, Book 70, Hadith 549 (Sunnah.com: https://sunnah.com/bukhari:5646)

Muhammad’s death shows that the Jewess was right, and Muhammad therefore stands condemned as an accursed false prophet even according to the Quran’s own criterion.

Further Reading

How Allah killed his prophet

Was Muhammad certain of his Salvation?

Revisiting the Uncertainty of Muhammad's Salvation 

Muhammad and Poison

Endnotes

(1) According to the Holy Bible, Jesus Christ has the power over life and death, and is able to strike false prophets and unrepentant sinners dead while reigning from/in heaven:

“And when I saw Him, I fell at His feet as dead. But He laid His right hand on me, saying to me, ‘Do not be afraid; I am the First and the Last. I am He who lives, and was dead, and behold, I am alive forevermore. Amen. And I have the keys of Hades and of Death.’” Revelation 1:17-18 New King James Version (NKJV)

“And to the angel of the church in Thyatira write, ‘These things says the Son of God, who has eyes like a flame of fire, and His feet like fine brass: “I know your works, love, service, faith, and your patience; and as for your works, the last are more than the first. Nevertheless I have a few things against you, because you allow that woman Jezebel, who calls herself a prophetess, to teach and seduce My servants to commit sexual immorality and eat things sacrificed to idols. And I gave her time to repent of her sexual immorality, and she did not repent. Indeed I will cast her into a sickbed, and those who commit adultery with her into great tribulation, unless they repent of their deeds. I will kill her children with death, and all the churches shall know that I am He who searches the minds and hearts. And I will give to each one of you according to your works.”’” Revelation 2:18-23 NKJV 

This means that Christ would have been the one who killed Muhammad by having him die a shameful, painful, humiliating death caused by the poison sheep which a Jewess fed him.