We have inquired into some of the most important doctrines of Christianity, which form parts of both the Protestant and the Roman Catholic creeds. Our examination has led us to the conclusion that the doctrines of the Trinity, the Divinity of Jesus, the Divine-Sonship of Jesus, the Original Sin and the Atonement are neither rational nor in conformity with the teachings of Jesus. These dogmas took shape long after Jesus, as a result of pagan influence. These dogmas show that Christianity has deviated considerably from the religion of Jesus.
Islam is a revival and restatement of the religion of Jesus and of all other prophets. The religion revealed to the Prophets of various nations was the same, but in the course of time it had been misinterpreted and become mixed up with superstitions and degenerated into magical practices and meaningless rituals. The conception of God, the very core of religion, had become debased by (a) the anthropomorphic tendency of making God into a being with a human shape and human passions, (b) the association of other persons with the One and only God in His Godhead (as in Hinduism and Christianity), (c) by the deification of the angels (eg., the Devas in Hinduism, the Yazatas in Zoroastrianism and, perhaps, also, the Holy Spirit in Christianity), (d) by making the prophets into avatars or incarnations of God (e.g., Jesus Christ in Christianity, the Buddha in Mahayana Buddism, Krishna and Rama in Hinduism), and (e) by the personification of the attributes of God into separated Divine Persons (e.g., the Christian Trinity of the Father, the Son and the Holy Spirit, the Hindu Trimurti of Brahma, Vishnu and shiva, and the Amesha Spentas of
Zoroastrianism). The Prophet Muhammad (pbuh) criticized all these irrational theological trends and restored to their pristine purity the conception of God as the One Eternal Reality (As-Samad), the Creator and Sustainer of all the worlds (Rabb-ul-'Alamin), the Loving-King (Ar-Rahman), the All-Merciful (Ar-Rahim) the All-Forgiving (Al-Ghaffar), the All-Mighty (Al-`Aziz), the All-Knowing (Al-`Alim), the Holy (Al-Quddus), the All-Embracing (Al-Wasi`). He purged religion of all superstitions, errors and meaningless ceremonies, widened its scope to make it a source of inspiration and guidance to the whole human race, and united the peoples of all races, colors and nations into one universal brotherhood.
Islam is a Religion without a mythology. Its teachings are simple and rational. Its appeal is to human reason and conscience. The truth of the Islamic doctrine of the Unity and Goodness of God is brought home to us by the study and contemplation of the cosmos, where we find the all-pervading unity behind the manifest diversity, by the teachings of all the prophets, by the experiences of the mystics of all religions and nations, and finally by the apologies of the Trinitarians, who, despite their belief in three Divine Persons, declare that there is but one God. The truth of the other Islamic principles follows logically from the belief in the Unity and Goodness of God. If God is One, all human beings are the creatures of the same God and are equal in His Sight - and hence the Islamic belief in the equality and brotherhood of all men and women. If God is the Creator and Nourisher of all the worlds, He must provide not only for the physical needs of man, but also for the moral and spiritual needs by revealing to man the path of truth and righteousness - and hence the Islamic belief in Divine Revelation. Moreover, the Divine Revelation must come wherever and whenever needed, and for revealing His Message, God must choose men who are completely devoted to truth, are leading godly and sinless life and can inspire others to follow the True Path - and hence the Islamic belief in the prophets of all nations. And finally, if God is the God of Goodness and His Plan in creating the world and making man a free moral agent is not frivolous and meaningless, there must be the life-after-death, where men may reap the fruits of their beliefs, intentions and actions and continue their blissful journey to God and in God - and hence the Islamic belief in the Hereafter.
The famous Italian Orientalist, Dr. Laura Veccia Vaglieri, writes the following about the rational and universal spirit of Islam in her book An Interpretation 0f Islam:
"The Arabian Prophet, with a voice which was inspired by a deep communion with his Marker, preached the purest monotheism to the worshippers of fetish and the followers of a corrupted Christianity and Judaism. He put himself in open conflict with those regressive tendencies of mankind which lead to the association of other beings with the Creator."
"ln order to lead men to a belief in one God, he did not delude them with happenings which deviate from the normal course of nature â€” the so-called miracles; nor did he compel them to keep quiet by using celestial threats which only undermine man's ability to think. Rather, he
simply invited them, without asking them to leave the realm of reality, to consider the universe and its laws. Being confident of the resultant belief in the one and indispensable God, he simply let men read in the book of life. Muhammad Abduh and Ameer All both state that Muhammad was content to appeal to the intimate conscience of the individual and to the intuitive judgment
After quoting some relevant verses of the Glorious Qur'an, the learned author continues:
"Thanks to Islam, paganism in its various forms was defeated. The concept of the universe, the practices of religion, and the customs of social life were each liberated from all the rnonstrosities which had degraded them, and human minds were made free of prejudice. Man finally realized his dignity. He humbled himself before the Creator, the Master of all mankind."
"The spirit was liberated from prejudice, man's will was set free from the ties which had kept it bound to the will of other men, or other so-called hidden powers, priests, false guardians of mysteries, brokers of salvation, all those who pretended to be mediators between God and
man and consequently believed that they had authority over other people's wills, fell from their pedestals. Man became the servant of God alone and towards other men he had only the obligations of one free man towards other free men. While previously men had suffered from the injustices of social differences. Islam proclaimed equality among human beings. Each Muslim was distinguished from other Muslims not by reason of birth or any other factor not connected with his personality, but only by his greater fear of God, his good, deeds, his moral and intellectual qualities."
Islam is the universal message of Unity - the Unity of God, the unity of all religions, the unity of the prophets of all the nations, and the unity of all mankind.
 Laura Veccia Vaglieri, Apologin dell Islamismo, translated into English as An Interpretation of Islam by Dr. Caselli, pp. 30,31
 Laura Veccia Vaglieri, Apologies dell Islamismo, pp. 33,34.