Universalism

Universalism refers to religious, theological, and philosophical concepts with universal ("applying to all") application or applicability. It is a term used to identify particular doctrines considering all people in their formation. In religion and theology, "universalism" is a principle that asserts that all people are under the consideration and love of God, and that theological concepts (doctrines) which conform to this concept are in fact more in accord with the divine concepts.

A church or community that calls itself Universalist may emphasize the universal principles of most religions and accept other religions in an inclusive manner, believing in a universal reconciliation between humanity and the divine. For example monotheistic religions like Judaism, Christianity, and Islam still claim a universal value of their doctrine and moral principles because they feel they are inclusive.
A belief in one common truth is also another important tenet: the living truth is seen as more far-reaching than national, cultural, or religious.

Christianity

In Christianity, Universalism refers to the belief that all humans can be saved through Jesus Christ and eventually come to harmony in God's kingdom. A related doctrine, apokatastasis, is the belief that all mortal beings will be reconciled to God, including Satan and his fallen angels. Universalism was a fairly commonly held view among theologians in early Christianity: In the first five or six centuries of Christianity, there were six known theological schools, of which four (Alexandria, Antioch, Cesarea, and Edessa or Nisibis) were Universalist, one (Ephesus) accepted conditional immortality, and one (Carthage or Rome) taught the endless punishment of the lost. The two major theologians opposing it were Tertullian and Augustine.
In the seventeenth-century and eighteenth-century Europe and America, other Christian reformers came to believe in a universally loving God and felt that God would grant all human beings salvation. They became known as the Universalists.

Hinduism

Hindu Universalism denotes the ideology that all religions are true and therefore worthy of toleration and respect. Veneration for all other religions was articulated by Gandhi:
"After long study and experience, I have come to the conclusion that [1] all religions are true; [2] all religions have some error in them; [3] all religions are almost as dear to me as my own Hinduism, in as much as all human beings should be as dear to one as one's own close relatives. My own veneration for other faiths is the same as that for my own faith; therefore no thought of conversion is possible." (M. K. Gandhi, All Men Are Brothers: Life and Thoughts of Mahatma Gandhi as told in his own words, Paris, UNESCO 1958, p 60.)
In Ananda Marga, a branch of Hinduism, Universalism refers to the idea that energy and matter are evolved from cosmic consciousness. Thus, all created beings are of one universal family. This is an expansion of humanism to include everything as family, based on the fundamental truth that the universe is a thought projection from the Supreme.

Judaism

Judaism teaches that God chose the Jewish people to be in a unique covenant with God, and one of their beliefs is that Jewish people were charged by the Torah with a specific mission — to be a light unto the nations, and to exemplify the covenant with God as described in the Torah to other nations. Not explicitly a Universalist theology, this view, however, does not preclude a belief that God also has a relationship with other peoples — rather, Judaism holds that God had entered into a covenant with all mankind as Noachides, and that Jews and non-Jews alike have a relationship with God.

Islam

Muslims believe that God has sent revelations to prophets throughout human history, of which the Holy Qur'an delivered to Muhammad is the last, intended to reiterate and bring final clarity to God's instructions, in order to bring peace and harmony to humanity through Islam (submission to God). Islam expressly recognizes the legitimacy of prior monotheistic religions, such as Judaism and Christianity, at least as they were originally revealed. Muhammad and his successors in the Khilafat sought to put into practice the regime of justice commanded by God in the Qur'an to ensure the security of the lives and property of non-Muslims under the dhimmi system, as well as according them certain rights of worship. The Qur'an identifies Jews, Christians, Zoroastrians, and "Sabi'un" or "baptists" (usually taken as a reference to the Mandeans and related Mesopotamian groups) as "people of the book" entitled to recognition and protection as religious communities. At various times, this status has been extended to other religious groups, such as Manichaeans and Hindus, although other Muslims have disagreed with their dhimmi status, and even rejected it for Zoroastrians and Mandeans despite the fairly clear command of the Qur'an.
Thus Islam carries a kind of universalist idea in its core concept of God's revealing work to all humankind, even though for most Muslims this does not entail the belief that all will be saved in the end. It is believed that Islam, as the final form of religion God revealed, offers the best system by which salvation can be attained, and its worldwide spread is seen as a development towards a final unity of humankind within this religion. The Muslim ideal of universal brotherhood is the Hajj (pilgrimage to Mecca) prescribed by Islam. Each year, close to three million people from every corner of the globe assemble in Mecca to perform Hajj and worship God. No individual can be identified as a king or pauper because every man is dressed in ihram clothing. Although some forms of Islam espouse predestinarian ideas, most schools of thought within the religion place ultimate responsibility with individual human decision; and since Islam has no concept of human debilitation comparable to the Christian concept of original sin, in theory, there is nothing preventing a universalist resolution of human fate within the Islamic belief system.