Good evening. I speak tonight not just to the Muslim world, but to all men and women of good will.
I speak as president of a secular republic founded to secure for its people the rights with which we are all endowed by our creator; I speak as a Christian in a Christian-majority country and as a black man in a white-majority nation.
I speak as a community organiser - as one who has studied how the powerless can find power.
And as a professor of law - as one trained to seek justice on the basis of both principle and hard fact.
I speak as a man who broke with my minister of many years, after I found that his preaching included messages I know to be horribly false.
Let us begin with the so-called "Islamic State" (IS). I've heard a few complaints about my saying the IS is not Islamic; let me clarify.
What the Islamic State is, is a cheap and horrible fake - a con job.
Consider: The IS claims to be restoring the "pure Islam" of a past era, either of the time of the Prophet and the early caliphs, or of the later, medieval caliphates.
Yet, what - beyond its snuff videos - is the IS most known for? For slaughtering Christians, Yezidis and other non-Muslims, or expelling them from areas it controls.
Strange: These very same peoples survived and even thrived under Islamic rule for more than a thousand years, including under all the caliphs that IS cites as upholding "true Islam".
What the IS tells other Muslims about its brand of Islam, in other words, is an outright lie.
I submit to you that, as a simple matter of fact, Islam itself has prospered most when it has embraced such tolerance - and that we can see this from the time of the Prophet and beyond, when Islam exploded in a matter of decades from a handful of men to half the civilised world.
For, in the centuries before Mohammed, the Christian rulers of the Eastern Roman Empire had ruthlessly and bloodily sought to stamp out Christian worship that did not conform to their Orthodox faith.
These savage campaigns decimated whole populations.
And then the Prophet and his armies rode in, and said to these Christians, and also the Jews, "Accept our rule and you may worship as you will - you'll just have to pay a tax."
No, this wasn't much like the religious tolerance now practised in the West. But it was far greater tolerance than the Byzantine Christians offered.
This principle of tolerance continued to bolster Islam and its culture for centuries. Maimonides, one of the greatest Jewish sages of all time, lived his entire life under Muslim rule - enriching not only Jewish understanding, but also laying the groundwork for thinkers of Islam's Golden Age, such as Avicenna, Averroes and Al-Farabi.
Well into the 17th century, Istanbul surpassed non-Muslim Europe in wealth and cosmopolitan glory.
And among the many factors behind the West's rise thereafter was that - over the painful course of Reformation, counter-Reformation and centuries of faith-based war - it finally matched, and then surpassed, the Islamic world in tolerance of religious differences.
Today, the lack of tolerance within Islam is a grievous weakness. In Iraq, Sunnis fear oppression by the Shia-led government in Baghad.
Indeed, the sectarian misrule of then-prime minister Nouri al-Maliki opened the door to the IS's invasion of Iraq.
Even now, those fears are what make it so hard to defeat the Islamic State.
When I brought our American troops home from Iraq in 2011, I believed Iraq's Sunnis and Shia had learned enough about how to co-exist.
I cannot express the depth of my sorrow that Iraq's elected leader chose a different course.
By contrast, look at Egypt, with its long, proud tradition of tolerance.
In fact, it was a threat to that tradition - fears that elected leaders were imposing an intolerant, Islamist regime - that prompted the vast, nationwide protests that led to the fall of President Mohamed Morsi.
I know my words on tolerance conflict with what many now claim is the truth of Islam. The Islamic State's embrace of blood-drenched hatred is only the most distilled form of an intolerance preached in mosques across the planet.
But I suggest that Muslims of goodwill can and must recognise this trend as a modern innovation, contrary to the faith of their fathers.
As a man of faith, I know it is the duty of every believer to do his or her own best to determine the will of the divine.
We may consult authorities, but authorities can conflict - and even the most learned scholar can be wrong.
Indeed, it is our duty to question mortals who claim religious authority - whether Christian or Hindu, Muslim or Jew. For authority is power - and men seek power for reasons good and ill.
This is a painful universal truth - but particularly urgent, I suggest, for Muslims today, facing such clear efforts among Sunni and Shia alike to use the words of the Koran to serve not the will of Allah, but their own.
Here, I'll put on my community-organiser hat. (Smiles). Huh - it's been a while.
I want to tell you: You have power.
Ask: Who pays the leader of your Friday prayers? Who provides the texts that teach your children of your faith? Should the wealthy determine what is taught as the truth of Islam?
The leader of your prayers, my friends, should uplift, not degrade; speak to your better angels, not to demons of his own creation.
The leader of your prayers should understand the rich history of your faith, how through tolerance it gave glory to Allah - and how intolerance, proclaimed by those who would turn Islam from Allah's ends to their own, is the greatest threat it faces today.
Good night.
Mark Cunningham is executive editorial page editor at the New York Post. This column originally ran in the New York Post.