One of the great canards of the post-9/11 world — promoted by theists and nontheists, conservatives and leftists, Democrats and Republicans alike — is that there are three Abrahamic faiths: Judaism, Christianity, and Islam.

But is that really true? If the three faiths worship the same God and preach His word, then there should be clear and compelling evidence of interconnection and aligned essential doctrines.

God's sacred lineage

Abraham was God's first patriarch, his descendants were God's chosen people, and the Lord God guided them — at great cost and peril — to the promised land.

Why is there the need to graft on to this historically and logically robust faith history the tale of Muhammad, which is supported only by legend and perhaps shards of archeological data?

The Jews, meanwhile, were the people through whom God sent His son, Jesus Christ, the messiah. Jesus was a holy, just, virtuous, believing Jew, and what He taught springs directly from the Old Testament. His ministry was ultimately a futile effort to convince His ethnic brothers to follow Him as their redeemer.

Jesus was betrayed by His own people and crucified by the Romans. His death, in substitutive atonement for the sins of humanity, was followed by His resurrection, and the risen Christ tasked His apostles to spread His word beyond the Jews to the gentiles, thus laying the foundation for Christianity, a descriptive moniker that came into common use around the end of the first century A.D.

Biblical genealogy and history are intricate and logical. Like all genealogy and history of the ancient world, they have gaps (which do not diminish their spiritual authority), and a great deal of both spring from oral tradition, which was eventually codified.

The fact that biblical genealogy and history are written in such painstaking detail in both the Old and New Testaments give them each spiritual and chronological heft, as does the fact that scholars have recovered thousands of manuscript copies and fragments totaling hundreds of thousands of pages.

Legend, not lineage

This brings us to the issue of whether Islam is really an Abrahamic faith.

Abraham was father of Ishmael, by his slave Hagar, who was banished from Abraham's household by Abraham’s wife, Sarah, even though she facilitated their union. God promised Hagar that Ishmael would be a great man and the father of many nations. Ishmael’s life and sons are detailed in Genesis 25 and then again in 1 Chronicles 1. Then he and his sons are never spoken of again.

The book of Genesis, written by Moses, likely dates to around 1200 B.C., even though its final form was not completed until centuries later. This means that the story of Abram, who becomes Abraham, is even older than that because it would have been told to Moses as oral history. So Abraham may have lived as long ago as 2000 B.C.

Yet Muhammad, the prophet of Islam who is supposedly descended from Ishmael, was not born until 570 A.D., which creates a time gap of more than 2,500 years. And for this span of more than two millennia, there are no documents that directly connect Muhammad to Abraham or Ishmael. There is only Islamic oral tradition or legend (known as Hadith), nearly all of which were produced a century or more after Muhammad’s death in 632 A.D.

Conversely, there is no doubt about the connection of the Old and New Testaments. They tell a continuous, coherent, logical, prophetically rich, and frequently archaeologically confirmed story of the journey of the Israelites to the promised land and the life and death of Jesus.

Why, then, is there the need to graft on to this historically and logically robust faith history the tale of Muhammad, which is supported only by legend and perhaps shards of archeological data?

Biblical appropriation

Even though there is no written genealogy from Ishmael to Muhammad, there is significant biblical appropriation in the Quran. In fact, plagiarism might be a better word.

For example, Allah created the heavens and the earth in six days (Surah 7:54; for the Quranic novitiates, the Quran is organized by the length of each Surah [chapter], from the longest, called the Opener to the shortest 114th, Mankind). Abraham’s name first appears in Surah 2. In total, Abraham’s name appears 69 times in the Quran; Jesus appears 25 times, Mary 34 times, and Moses 136 times. In 3:67, the Quran states that “Abraham was not a Jew, nor was he a Christian, but he was a Muslim hanif (montheist), and he was not one of the idolators.”

RELATED: Why progressives want to destroy Christianity — but spare Islam

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While Muhammad was quite open to biblical appropriation of names, he was not so keen on Christian doctrine: Muslims deny the Trinity (“do not say Three”; 4:171) and the crucifixion (“they did not kill him nor crucify him”; 4:157). The denial of the crucifixion leads to an implicit denial of the resurrection; if Jesus was not crucified, then He could not have been resurrected, but He was called to heaven by Allah himself (4:158).

The Quran calls Jesus "messiah" and righteous, but simultaneously denies that He is the son of God (“The Messiah, the son of Mary, was no more than a messenger, messengers passed away before him”; 5:75). In fact, in these things, the Muslims have much more in common with Jews than either group has with Christians.

Ironically, this trio of denials of core Christian beliefs puts Muslims in league with Martin Luther King Jr., who denied the virgin birth, which Muslims accept, but they reject Allah's paternity of Jesus (see 3:45-47, 9:30, 6:100, and 112:3 for examples).

Muhammad writes that man does not have free will (2:6 and 2:7, among many others); Allah decides and animates all things (3:47 and 40:68). Allah will decide what both believers and nonbelievers do (16:93) and what will happen to them (24:40). Even nonbelievers who wish to believe will not be allowed to do so unless permitted by Allah (10:100).

Muslims are commanded to defeat nonbelievers in jihad (8:39 and 9:5); those who fight and die go to paradise, as do those who fight and live (4:74). Nonbelievers are to be treated as second-class citizens and pay tribute unless they convert, or they may be killed (9:29). Jews and Christians are regarded, respectively, as those who have earned Allah’s anger and those who have gone astray (1:6).

In the Bible, acts of sexual immorality are identified as an abomination to the Lord, right from the beginning of the Old Testament. Deuteronomy 22:5 says, “The woman shall not wear that which pertaineth to a man, neither shall a man put on a woman’s garment: for all that do so are an abomination unto the Lord thy God"; and Leviticus 18:6-20 describes the Lord’s abhorrence for the sin of incest. Paul’s epistles showcase his scorn for sexual anarchy.

By contrast, Muslim men may marry Jewish or Christian women after the women convert, but sex with a believing slave girl is preferable in the meantime (2:221). Muslim men are also told that they may marry multiple women (i.e., polygamy), and they have no obligation to treat them equally (4:3). The “houris,” or wide-eyed, voluptuous women of paradise, await all believers (Surahs 44, 55, 56, and 78; the much-ballyhooed 72 virgins are not Quranic, they are from a Hadith of Muhammad).

The overall impression of the God of the Bible is that He is a holy and just God, whose moral boundaries and demands set exceedingly high standards of conduct, and Jews of the Old Testament repeatedly fail to hit their marks. Their failures allowed God to show Himself as merciful and loving because He relents in His anger and forgives His people, effectively giving them the chance to start again.

Different gods

It is true that the Quran also refers to Allah in this manner repeatedly. But that is just part and parcel of the appropriation.

The Old Testament’s story of God’s love for, and strife with, His chosen people over their conduct repeats many times because God’s communication through His prophets ultimately proves ineffective at bringing about the lasting behavioral and devotional change that He demands. The God of the Bible never gives up, however, because He loves His children and seeks their betterment only for their own good, a framing of morality that they simply cannot endure because it requires patience, reverence, and discipline.

In the New Testament, God decides to confront His people face-to-face, live among them as a man, and teach them by looking them in the eye. So He sends His son, Jesus Christ, who is eternal and has borne witness to the entire chronology of creation, to live a perfect and sinless life, teach the lessons of the Old Testament, and entreat His people — the first-century Jews — to follow Him in pursuit of salvation and eternal life.

Despite all the travails, challenges, and even violence of the Bible, it is an uplifting story of love, trust, hope, and faith that ends in glory.

The same cannot be said of the Quran, in which an omnipotent god views his people as automatons commanded to do his will. Some verses abrogate others, and there really is no story told but just an endless series of dos and don’ts that end either in hell or paradise with wide-eyed houris.

Ask the people of Minnesota and Michigan and France and the United Kingdom how that’s working out.

Given the lack of a documentary interconnection, the doctrinal discrepancies between the two faiths as expressed in their central holy books raise this critical question: How is it spiritually conceivable that the two books represent the work of the same God?

Would the God who never gives up on His people and venerates marriage and family be the same God who commands men to marry unbelieving women only after they convert and have relations with slave girls while they wait? Would the God who empowers humans with free will and petitions them to follow Him to heaven by living lives of righteousness and virtue be the same God who commands the deaths of nonbelievers, specifically Christians and Jews (4:89), simply because of their unbelief? Would the God who sacrifices His own son on a Roman cross be the same God who appropriates the names, events, and stories of the Bible and relabels them to make them His own in a new book?

The Quran, like a bad Hollywood production, simply takes the biblical plots and characters and changes the name of God from "I AM" to Allah. Adam, Aaron, David, Elijah, Isaac, Job, Jonah, Joseph, Lot, Noah, Solomon, Zechariah, the Psalms, Gabriel, Michael, Noah’s ark, and even the Ark of the Covenant (2:248) all make cameo appearances.

Most importantly, would the God who wants peace and fights wars only against those who seek to eradicate His chosen people (such as the Amorites, Philistines, Canaanites, Hittites, Jebusites, and Perizzites) so that His people can live freely under His law be the same God who commands jihad and the imposition of sharia law, both of which seek to coerce conversion or kill those who will not convert?

Ask the people of Minnesota and Michigan and France and the United Kingdom how that’s working out.

Fruit reveals truth

To say that the God of the Bible is spiritually and doctrinally the same as Allah of the Quran beggars logic, ignores history, and requires that you willfully disregard the written word in each book.

The canard that Islam is an Abrahamic faith is a way of facilitating a connection between evil and goodness for political purposes in order to provide the evil with the fig leaf of acceptance by affiliation rather than by word and deed.

The God of the Bible, and those who follow His word, produced the freest, safest, cleanest, most generous, and most prosperous nations in human history. Islam, on the other hand, has produced — as the late Samuel P. Huntington wrote in his tour de force "Clash of Civilizations" — a cadre of nations that are never simultaneously at peace with all their neighbors and within their own borders.

That was true when he wrote it in 1996, and it is still true today.

Maybe the holy war now being waged between Islam and what remains of a weak-kneed and addle-brained Christendom is why Jesus says in both Matthew and Revelation that He comes with a sword to separate those who deny from those who follow Him.

When you consider whether it is at all likely that Islam is Abrahamic, remember what the redeemer says in Matthew 7:16-20: "Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles? Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them."

That is all you need to know to stop saying — and believing — that Islam is an Abrahamic faith.