Why Not Islam — VacantTomb

Muhammad as Prophet

The entire structure of Islam rests on the prophethood of Muhammad. The Quran is the Quran because Muhammad received it. The Five Pillars, the Sharia, the practice of Islam — all of it derives its authority from the claim that Muhammad was the final and greatest prophet, the Seal of the Prophets, through whom God delivered his complete and final revelation to humanity.

This claim requires evaluation on the same terms as any other historical claim about a religious figure. What are the criteria for prophethood? Does Muhammad meet them? What is the evidence for and against his prophetic claims? These questions are addressed here with the same directness that the Why Christianity Foundation applied to the claims of Jesus.

The biblical standard for prophethood

The Old Testament — which Muhammad claimed to accept and the Quran affirms as divine revelation — contains an explicit test for prophethood in Deuteronomy 18:20–22:

Deuteronomy 18:20–22

ESV

But the prophet who presumes to speak a word in my name that I have not commanded him to speak, or who speaks in the name of other gods, that same prophet shall die. And if you say in your heart, ‘How may we know the word that the LORD has not spoken?’ — when a prophet speaks in the name of the LORD, if the word does not come to pass or come true, that is a word that the LORD has not spoken; the prophet has spoken it presumptuously. You need not be afraid of him.

The standard is clear: a genuine prophet of God must have predictions that come true. A failed prediction establishes false prophethood. This is not a standard invented by Christian apologists — it is a standard the Quran itself affirms by accepting the authority of the Torah.

Muhammad's prophetic claims and predictions

The promise of Roman victory (Surah 30:2–6): The Quran's opening to Surah 30 contains a prediction:

Surah 30:2–4

Sahih Int...

The Romans have been defeated in the nearest land. But they, after their defeat, will overcome within three to nine years. To Allah belongs the command before and after.

This prediction — that the Romans would defeat the Persians within "a few years" — was eventually fulfilled, but the timeline is contested. The Byzantine-Sassanid War lasted from 602 to 628 AD; the Byzantine recovery came approximately 14 years after the initial defeats, which may or may not fall within the timeframe the Quran specifies (the Arabic bidh'i sinin means "a few years," typically 3–9). The difficulty is that the original unvoweled Arabic text could support different timeframes, and Islamic scholars have adjusted the reading when the prediction proved difficult to verify within the expected period. This is not a prediction that provides independent evidence of prophetic foreknowledge — the ambiguity of the timeframe makes it impossible to falsify.

Muhammad's uncertainty about his own salvation: The Hadith records Muhammad expressing uncertainty about whether his own good deeds would be sufficient for salvation:

By Allah, though I am the Apostle of Allah, yet I do not know what Allah will do to me.
MuhammadSecular historian— Sahih Bukhari 5:266

This is a remarkable statement for the person claimed to be God's final and greatest prophet to make. Muhammad himself, according to Islam's most authoritative sources, did not know whether he would be saved. If the prophet cannot have assurance, what hope does any ordinary Muslim have? And what does this uncertainty reveal about the nature of the relationship between Allah and even his most favored servants?

The "Satanic Verses" incident: The early Islamic sources — including Ibn Ishaq (the earliest biographer of Muhammad), al-Tabari (one of the most authoritative Islamic historians), and al-Waqidi — record an incident in which Muhammad received and recited verses that accepted three pagan goddesses (Allat, al-Uzza, and Manat) as intercessors with Allah. The verses were: "These are the elevated cranes, whose intercession is to be hoped for." The Meccans were pleased; the Muslims were confused. Muhammad subsequently recanted, claiming that Satan had inserted these verses without his knowledge.

The theological implications are severe. If Satan can insert false verses into prophetic revelation without the prophet's knowledge or resistance — if the channel of divine communication is corruptible — then what guarantee exists that any other verse is not similarly corrupted? The episode undermines the claim of perfect divine protection of the Quranic revelation at its foundation.

Muslim scholars have debated the authenticity of this report intensively. Some accept it (Ibn Ishaq, al-Tabari) and attempt to explain it theologically; others reject it as a fabrication. But the report's presence in early authoritative Islamic sources, and the difficulty of explaining why anyone would fabricate it, gives it historical credibility that is hard to dismiss.

Claimed prophecies of Muhammad in the Bible: Deuteronomy 18

The Quran claims that Muhammad's coming was prophesied in the Bible:

Surah 7:157

Sahih Int...

Those who follow the Messenger, the unlettered prophet, whom they find written in what they have of the Torah and the Gospel, who enjoins upon them what is right and forbids them what is wrong and makes lawful for them the good things and prohibits for them the evil...

The two biblical passages most frequently cited by Muslim apologists as predicting Muhammad are Deuteronomy 18:18 and John 14:16. Each deserves careful examination.

Deuteronomy 18:18: "I will raise up for them a prophet like you from among their brothers. And I will put my words in his mouth, and he shall speak to them all that I command him."

The Muslim argument: this prophet "like Moses" — who received divine words directly put in his mouth — is Muhammad. The Christian response: the New Testament explicitly applies this prophecy to Jesus. At the Transfiguration, the divine voice says "Listen to him!" (Matthew 17:5) — echoing the Deuteronomy command to heed the coming prophet. Peter explicitly identifies Jesus as the fulfillment of this prophecy in Acts 3:22–23. Stephen does the same in Acts 7:37.

Moreover, the specific criteria of the prophecy fit Jesus better than Muhammad on multiple points:

"From among their brothers" — referring to Israelites, not Arabs. Jesus was Jewish; Muhammad was Arab
"Like Moses" — Moses performed signs and wonders. Jesus performed miracles attested by multiple sources; the Quran itself (Surah 17:59) acknowledges that Muhammad's contemporaries demanded miraculous signs and did not receive them
"Put my words in his mouth" — Jesus spoke with divine authority ("You have heard it said... but I say to you"), not merely as a conduit for divine dictation. The pattern of Jesus's teaching matches this description in a way that Muhammad's claimed reception of the Quran (auditory revelation that he repeated) does not

The Paraclete argument: John 14:16

The second major Islamic claim is that Jesus's promise of the Paraclete (Comforter/Helper) in John 14:16 is a prediction of Muhammad. The argument depends on a proposed emendation of the Greek text.

The text: "And I will ask the Father, and he will give you another Helper (parakletos), to be with you forever."

The Muslim argument: The original Greek word was not parakletos (Comforter/Advocate) but periklutos (praised one) — which is a Greek translation of the Arabic Ahmad, one of Muhammad's names. The Christians corrupted the text, changing periklutos to parakletos.

This argument fails on every evidential point:

Textual evidence: There is no Greek manuscript anywhere in the world — not one of the 5,800+ Greek NT manuscripts — that reads periklutos instead of parakletos in John 14:16. The argument requires believing that a textual corruption occurred in every single manuscript of the Gospel of John in every single location, leaving no trace of the original reading. This is the same problem as the general tahrif argument — the manuscript tradition makes it impossible.

The description of the Paraclete: John 14:16 says the Paraclete will be "with you forever" — a description that cannot refer to a man who was yet to be born, would live for approximately 60 years, and would die. It also says "you know him, for he dwells with you and will be in you" — present tense, speaking to the disciples then alive. The Paraclete is someone the disciples already know. Muhammad was not born until approximately 570 AD.

John 14:26 identifies the Paraclete: "the Helper, the Holy Spirit, whom the Father will send in my name, he will teach you all things and bring to your remembrance all that I have said to you." The Paraclete is explicitly identified as the Holy Spirit — not a future prophet.

John 16:7 says: "It is to your advantage that I go away, for if I do not go away, the Helper will not come to you." The Paraclete's coming is contingent on Jesus's departure. This is fulfilled at Pentecost (Acts 2), when the Holy Spirit descends on the disciples in Jerusalem — approximately 570 years before Muhammad.

The Paraclete argument requires: a textual corruption in every Greek manuscript, ignoring the text's own identification of the Paraclete as the Holy Spirit, ignoring the present-tense descriptions that require the Paraclete to be already known to the disciples, and ignoring the Pentecost account that the earliest Christians understood as the Paraclete's arrival. None of these requirements are met.

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Muhammad as Prophet

Islam rests on the prophethood of Muhammad. The biblical test for prophethood requires accurate predictions. The Satanic Verses incident raises questions about the reliability of the revelation channel. The claimed biblical prophecies about Muhammad — Deuteronomy 18:18 and the Paraclete — both refer explicitly to Jesus and the Holy Spirit.

Key claims

—Deuteronomy 18:20–22 (affirmed by Quran): failed prediction equals false prophet
—Sahih Bukhari 5:266: Muhammad did not know if he would be saved
—Satanic Verses: Satan temporarily inserted false verses — recorded in Ibn Ishaq and al-Tabari
—Surah 17:59, 29:50: Muhammad's contemporaries demanded signs; Quran records Allah declining
—Deuteronomy 18:18: "from among their brothers" means Israelites not Arabs — fulfilled in Jesus per Acts 3:22–23
—John 14:16 Paraclete: no Greek manuscript reads periklutos; Paraclete identified as Holy Spirit in John 14:26

Scholars cited

Ibn IshaqEarliest Muslim biographer
Al-TabariAuthoritative Islamic historian

Other foundations

Why Christianity

Why Not Atheism

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