This article covers a list of beliefs and claims which are required in order for Islam to be true, or have been used by Muslims to defend Islam, and which are absurd, insane, and indefensible:

• Allah was actually trying to communicate that "the Gospel and Torah are completely corrupt, don't trust them", yet still gave verses like Surah 5:43-47, 5:68. Allah gave verses like this, knowing that literally every single page of the contemporary Torah and Gospel had been tampered with, and the entire narrative was corrupted and falsified
• The evil Jews, and evil early Christians, were somehow able to universally corrupt all the manuscripts of the Torah and Gospel, knowingly sending themselves to Hell and corrupting their own religion, which they then went on to follow anyway. There was not a bitter struggle by any Jews who had copies of the Scripture in other nations, nor did Allah help such a faithful group prevail, and this corruption was so complete that they got to every last manuscript ever found - even ones buried from before the time of Christ
• "None can change God's words" (Surah 6:115, 18:27) actually means "people can corrupt the vast majority of everything God ever inspired, and even wrote with His own hand (Sahih al-Bukhari 6614, Sahih Muslim 2652a)"
• The fact that the Torah and Gospel completely contradict Islam doesn't disprove Muhammad's claim to affirm their message (Surah 2:40-41, 3:3-4, etc.), since he affirmed an original Torah and Gospel which are lost, and no one can analyze to verify (except bits and pieces that we can use to support Islam, even when 95% of the surrounding context teaches explicitly against Islam, and has the same textual history as the passage we are using)
• Muhammad affirmed the same God that Moses and Jesus preached, despite never demonstrating awareness at any point in time of the special divine name of this God, repudiating the fact that He is a Father, and creating a religion bereft of the concept of blood atonement that Abraham pictured, Moses preached, and Jesus fulfilled
• The Quran, which is in a completely different style to either the Old or New Testament, was actually written by the same God that gave the Bible, even though the scant bits and pieces of the Old and New Testament that we uphold to support Islam still sound nothing like the Quran. Similarly, everyone in history sounded just like Muhammad, even maintaining his Arabic rhyming schemes when they spoke, and ending their statements with his same vague exaltations of God
• Muhammad is prophesied in both the Torah and the Gospel that the Jews and Christian had "in their possession" during the time of Muhammad (Surah 7:157), which we know beyond a shadow of a doubt is the same as our current Torah and Gospel
• The "Gospel" that Muhammad affirmed is actually a book given directly by God to Jesus, and no one knows what happened to it. Yet, because Muhammad said that he was mentioned in the Gospel that is in the possession of the Christians (Surah 7:157), at the same time, we must assert that Muhammad is somewhere in a modern collection of "Gospels", which are not books given directly from God to Jesus, and are instead second and third-person accounts of Jesus and His teachings
• Jesus was actually a Muslim, and so were His original followers. However, His original message, and the Gospel that Allah gave Him, have been totally lost, and His original Muslim followers left no trace whatsoever of ever having existed, despite having been given victory over their adversaries by Allah (Surah 61:14), and having been promised elevation until the Day of Resurrection (Surah 3:55)
• Jesus was born of a virgin, was sinless, performed many miracles, and was raised by Allah to Heaven so that He never died - none of which is true about Muhammad. Yet, Muhammad was a greater prophet - the only one fit to intercede for mankind (Sahih al-Bukhari 6565, etc.) - and "The Seal of the Prophets" (Surah 33:40). And, despite all of the things Allah did for Jesus, all that resulted from Jesus's prophethood was the creation of a gigantic false religion, thanks to Allah deceiving everyone by making it appear that He was crucified, when He was not (Surah 4:157), and not a single one of His "real" followers persisted or left a trace of existing
• Jesus prophesied of "A messenger to come after me, whose name is Ahmad" (Surah 61:6), yet this major fact somehow entirely escaped the historical record
• The Apostle Paul, who was a devout Jew who persecuted and killed those in the early Christian church, was actually the creator of modern-day Christianity. He did this somehow, despite opposition from Jews, who rejected Jesus as the Messiah, and the early "Muslim" Christians, who were, well, Muslims. He then managed to get all of the Apostles to follow him, and they all wrote many epistles to local churches of this new "fake" Christianity, the members of which - especially in the Jerusalem church - would have been contemporaries of Jesus and His "original Muslim followers". Yet, they were able to completely lie about literally everything that Jesus taught and did, and leave no evidence whatsoever of polemics or interaction with the "original Muslim followers" of Jesus
• The Apostle Paul totally corrupted Christianity and the message of Jesus, yet Allah failed to so much as mention him once, anywhere in the Quran or Hadith
• Mecca was God's first and most important center of worship (Surah 3:96), and Allah told Abraham to "call all people" to the pilgrimage to circle the Kaaba (Surah 22:25-29), yet not a single Jew or Jewish historian ever recorded such a thing, and neither did Moses (~500 years after Abraham) or David (~1000 years after Abraham), even though both are described in the Quran as devout Muslims. And, even though Mecca was God's first and most important center of worship for all of mankind, it remained a dusty village in the desert, utterly unknown to history, until the time of Muhammad
• The current Old Testament, for which we have indisputable BC manuscripts, is a cohesive narrative that is powerfully fulfilled in the current New Testament, which was indisputably written in the first century, yet that doesn't matter at all, and is proof of nothing, because these aren't the "Torah" and "Gospel" mentioned by the Quran, even though they are the only things that have ever been known to history as the Torah and Gospel
• Even though Christians and Jews affirm the same Old Testament, which is quoted many times from the time of Jesus in the New Testament and in Jewish sources, and is indisputably the Scripture that Jesus had, not a scintilla of evidence survived of Him warning us that the Torah was totally corrupted, but rather, the exact opposite (Matthew 5:17-18), even though the entire thing had been replaced with narratives involving blood atonement, God as Father, and other false things
• Muhammad didn't confuse Miriam the sister of Moses with Mary the mother of Jesus. Rather, "sister of Aaron" (Surah 19:27-28) refers to either her brother (mentioned nowhere in history before Muhammad), or her descendance from Aaron (even though that would be "daughter of Aaron", and neither epithet is used in Scripture or history of her, and she was descended from Judah, not Levi [Luke 3:26, Hebrews 7:14]). Also, the fact that she is said to be the daughter of Imran (Surah 3:33-39, 66:12) does not mean that he mistook her for Miriam, the daughter of Imran. Rather, it was a different Imran, mentioned nowhere in history before Muhammad
• Muhammad didn't conflate the story of Gideon and Saul in Surah 2:249-251. Rather, God actually did the exact same test on Saul's men that He did on Gideon's men in Judges chapter 7, and this was all lost to history until Muhammad set the record straight
• There was a man named Zul-Qarnain, who was able to build a wall of metal by stacking iron blocks between a mountain pass, then heating them in place, then pouring molten copper over them, such that entire viscous, savage tribes called Gog and Magog were unable to pass it, scale it, break through it, or tunnel under it. Not only was Zul-Qarnain able to build a wall like this, but the wall lasted for thousands of years, and will not fall until judgment day, when Gog and Magog will finally be released. Gog and Magog, who lived in the mountains, were unable to climb the mountains, scale the wall, or find a detour, and this wall, tribe, and mountain pass have never been found (Surah 18:92-100, 21:95-97)
• Muhammad didn't contradict relatively obscure Biblical commands like forbidding of swearing (Matthew 5:34-37, contradicted by Surah 24:6-9, etc.), and rules concerning divorced women (Deuteronomy 24:1-4, contradicted by Surah 33:37, 66:5) because he was ignorant of what the Bible said, but rather because originally, the previous prophets had taught the exact same thing, and others corrupted these doctrinal minutiae
• The Quran is perfect, well-written, miraculously beautiful, and compelling
• Aisha was a fully-grown 9 year-old woman, and psychologically ready for intercourse with a 54 year-old man, even though she was playing on swings (Sahih al-Bukhari 3894), and playing with dolls (Sahih an-Nasai 3378) when Muhammad consummated their marriage
• Allah gave Muhammad, and only Muhammad, permission to have sex with as many women as he wanted, including close relatives (Surah 33:50), and gave him the divorced wife of his own adopted son (Surah 33:37)
• The Hadith of the Fly (Sahih al-Bukhari 3320, 5782, Sunan ibn-Majah 3505, Sunan abu-Dawud 3844) is not an absurd, obviously-false claim, but rather a scientific miracle, or refers to some lost fly which cannot be analyzed to verify
• The God of the universe "revealed" as part of His eternal word, the Quran, that a man being breastfed by a woman ten times made him unlawful for marriage, then this was reduced to five within a single man's (Muhammad's) lifetime, then removed from the Quran entirely (Sahih Muslim 1452a-b, 1453a-d, Sunan ibn-Majah 1942-1944)
• The God of the universe allowed prostitution, and called it a "good thing" (Sahih al-Bukhari 4615, etc.)
• Women can get a yellow "discharge" during dreams and intercourse which determines how a child will look, i.e., which has genetic material (Sahih Muslim 311, Sahih al-Bukhari 3329, etc.)