Conformity to religious orthodoxy is the goal of indoctrination. For Islam, this means that Muhammad is the perfect example for Muslims and that Allah and the Quran are clear and flawless, inerrant, inviolable, and unchangeable.

Islamic orthodoxy's principles are authoritarian, patriarchal, intolerable, totalitarian, and supremacist and they are grounded on the precepts of divine law. We who were taught the principles of natural law have a different perspective on the world than brainwashed Muslims. We want substantiated justifications. However, the Quran, which contains God's Word, is considered to be the last word by Muslims. Verifiable justifications are useless if they conflict with the Bible.

The quickest way to lose your Islamic faith is by adopting natural law precepts. They’re antithetical to the divine law precepts Islam requires. If you hold fast to the infallibility of Allah and the Quran, they can never be wrong. This position is required by Islamic orthodoxy because if you allow for error (admit falsehoods), the entire religion is doomed.

Based on the revelations the Prophet Muhammad received, Islam emerged in the Arabian desert as a response to predominate local customs. 

Critics have questioned why, in several verses, God is addressed by humans rather than by Him, given that the Quran is God's revelation to humanity. While Islamic law (sharia), which is based on the hadith of Muhammad, commands adulterers to be stoned to death rather than given the death penalty, it ignores some of the divine commands or policies found in the Quran, such as the one that calls for the punishment of '100 lashes' for Zina (sex that occurs outside of marriage).

Since the 7th century AD, when Muhammad was criticized for preaching monotheism by his non-Muslim Arab contemporaries, as well as by the Jewish tribes of Arabia for what they saw as unjustified appropriation of Biblical figures and narratives and vituperation of the Jewish faith, there has been some criticism of Muhammad.

Because Muhammad was widely viewed in Christendom as a heretic or being afflicted by devils, several Western and Byzantine Christian theologians of the Middle Ages believed him to be a perverted, despicable man, a false prophet, and even the Antichrist. Some of them, including Thomas Aquinas, condemned Muhammad for the way he handled doctrinal issues and for promising eternal hedonistic pleasure.

Muhammad's genuineness as a prophet, his morality, his marriages, his ownership of slaves, and his psychiatric state have all been the subject of modern scrutiny. Muhammad has also come under fire for allegedly treating his adversaries with sadism and cruelty, particularly when the Banu Qurayza tribe invaded Medina.

Ayaan Hirsi Ali, a Somali-Dutch feminist writer, has referred to Muhammad as a 'tyrant' and a 'pervert' and attacked him for espousing ideas that are incompatible with democracy.

Three caricatures published by Hindus in the 1920s attacked Muhammad and marriages: Pandit Kalicharan Sharma's book Vichitra Jivan (meaning Strange Life) in 1923; Pandit Chamupati's anonymous pamphlet Rangila Rasul(meaning The Colourful Prophet) in 1924; and Devi Sharan Sharma's essay Sair-i-Dozakh (meaning The Trip to Hell) in 1927.

Sharma claimed in Vichitra Jivan that Muhammad experienced numerous evils, that all of his unions were unusual and unsuitable, and that he had epilepsy.

Sharma thoroughly dissected Muhammad's 'marvelous powers,' 'products of his body,' and all aspects of his 'marital and sexual connections,' concluding that such a person could not have been a supernatural prophet.

The basic issue for Muslim theologians about the morality of slavery, according to sociologist Rodney Stark, is that Muhammad 'purchased, sold, captured, and possessed slaves,' and his followers considered him the ideal role model to imitate.

Slavery existed in Arabia before the advent of Islam, and Muhammad never stated that he intended to outlaw the practice because he considered it to be 'part of the natural order of things.'

He did advocate for the improvement of slave conditions and urged his followers to treat them with more respect and compassion, both as human beings and as property, to ameliorate their lot in life.

His rulings made it much more difficult for people to become enslaved and under what conditions (including prohibiting Muslims from enslaving fellow Muslims), made it possible for slaves to become free, and considered setting free slaves a morally admirable deed. He legalized the marriage of his men's slaves and concubines who had been taken prisoner in battle.

Muhammad is charged by Norman Geisler with 'mercilessness' toward the Jewish tribes of Medina.

Geisler contends that Muhammad 'acted in revenge against those who mocked him,' 'had no aversion to politically expedient assassinations,' and 'was not indisposed to breaking commitments when he deemed it convenient.'   Muhammad was characterized as being ruthless and unfaithful in his treatment of his opponents by the Orientalist William Muir in his assessment of his character.

Muhammad has faced some of the most common historical criticism in the West due to his polygamous unions. Muslims frequently point out that Muhammad married Khadija bint Khuwaylid when he was 25 years old and remained monogamous with her for more than 24 years before she passed away. Khadija was a widow who was believed to be 40 years old at the time. Given that Muhammad refused to follow the stated limit of four women that he imposed on other men, Norman Geisler interprets Muhammad's marriages as a matter of moral inconsistency. According to Quran 33:50, Muhammad is exempt from the rule limiting men to four wives.

The Islamic prophet Muhammad was wed to thirteen different women. As a mark of respect, Muslims frequently use the word Umm al-Mu'minin before or after referring to them. Muhammad married Khadija, a widow when he was 25 years old. This couple was together for 25 years. He married a total of 12 women during his remaining years after her passing in 619 CE. Two of these wives—Khadija and Maria al-Qibtiyya—bear him children. Except for Aisha, all of Muhammad's spouses were divorcees or widows.

It's alleged that Muhammad treated his wives unfairly. He is charged with openly favoring Aisha among his living women, categorically ranking Khadija as his best wife overall, and using the Quranic stipulation to engage in unequal sexual relations with his wives. His acts caused his women to be envious of one another and to disagree with one another, and they 'illustrate the difficulties of husbands to offer equal respect to several wives.'

Muhammad reportedly experienced unexplained convulsions when he was inspired. In his revelations, Muhammad 'sometimes roared like a camel, foamed at his mouth, and poured with perspiration,' according to Philip Schaff (1819–1893).

Muhammad has drawn criticism for a number of oversights made during his prophethood, including the fact that he failed to clearly and unmistakably name the person, selection procedure, or institution that would succeed him after his death, the failure to compile the Quran into a final text (which was later accomplished during Uthman's Caliphate), and the failure to gather and codify his prophetic tradition.