Eschatology

Eschatology concerns expectations of the end of present age, human history, or the world itself. The end of the world or end times is predicted by several world religions, which teach that negative world events will reach a climax. Belief that the end of the world is imminent is known as apocalypticism, and over time has been held both by members of mainstream religions and by doomsday cults. In the context of mysticism, the term refers metaphorically to the end of ordinary reality and to reunion with the divine. Many religions treat eschatology as a future event prophesied in sacred texts or in folklore, while other religions may have concepts of renewal or transformation after significant events.
The Abrahamic religions maintain a linear cosmology, with end-time scenarios containing themes of transformation and redemption. In Judaism, the term "end of days" makes reference to the Messianic Age and includes an in-gathering of the exiled Jewish diaspora, the coming of the Messiah, the resurrection of the righteous, and the world to come. Christianity depicts the end time as a period of tribulation that precedes the second coming of Christ, who will face the rise of the Antichrist along with his power structure and false prophets, and usher in the Kingdom of God. The explicit description of a new earth is primarily found in Christian teachings. In later traditions of Islam, separate hadiths detail the Day of Judgment as preceded by the appearance of the Masīḥ ad-Dajjāl, and followed by the descending of ʿĪsā, which shall triumph over the false Messiah or Antichrist; his defeat will lead to a sequence of events that will end with the sun rising from the west and the beginning of the Qiyāmah.
Dharmic religions tend to have more cyclical worldviews, with end-time eschatologies characterized by decay, redemption, and rebirth. In Hinduism, the end time occurs when Kalki, the final incarnation of Vishnu, descends atop a white horse and brings an end to the current Kali Yuga, completing a cycle that starts again with the regeneration of the world. In Buddhism, the Buddha predicted his teachings would be forgotten after 5,000 years, followed by turmoil. It says a bodhisattva named Maitreya will appear and rediscover the teachings of the Buddha Dharma, and that the ultimate destruction of the world will then come through seven suns.
Since the development of the concept of deep time in the 18th century and the calculation of the estimated age of planet Earth, scientific discourse about end times has considered the ultimate fate of the universe. Theories have included the Big Rip, Big Crunch, Big Bounce, and Big Freeze. Social and scientific commentators also worry about global catastrophic risks and scenarios that could result in human extinction.

Etymology

The word "eschatology" arises from the Ancient Greek term wikt:ἔσχατος, meaning "last", and -logy, meaning "the study of", and first appeared in English around 1844. The Oxford English Dictionary defines eschatology as "the part of theology concerned with death, judgment, and the final destiny of the soul and of humankind".

Linear cosmology

Judaism

The main tenets of modern Jewish eschatology, in no particular order, include:

God will redeem Israel from the captivity that began during the Babylonian Exile in a new Exodus.
God will return the Jewish people to the Land of Israel.
God will restore the House of David and the Temple in Jerusalem.
God will raise up a regent from the House of David, the Jewish Messiah, to lead the Jewish people and the world and to usher in an age of justice and peace, the Messianic Age.
Non-Jews will recognize that the God of Israel is the only true god.
God will resurrect the dead.
God will create a new heaven and earth.

Judaism usually refers to the end times as the "end of days", a phrase that appears several times in the Tanakh. The end times are addressed in the Book of Daniel and in numerous other prophetic passages in the Hebrew scriptures, and also in the Talmud, particularly Tractate Avodah Zarah.
The idea of a Messianic Age, an era of global peace and knowledge of the Creator, has a prominent place in Jewish thought, and is incorporated as part of the end of days. A well-known passage from the Book of Isaiah describes this future condition of the world: "They shall beat their swords into plowshares and their spears into pruning hooks; nation will not lift sword against nation and they will no longer study warfare". Maimonides further describes the Messianic Era in the Mishneh Torah: "And at that time there will be no hunger or war, no jealousy or rivalry. For the good will be plentiful, and all delicacies available as dust. The entire occupation of the world will be only to know God;... the people Israel will be of great wisdom; they will perceive the esoteric truths and comprehend their Creator's wisdom as is the capacity of man. As it is written : 'For the earth shall be filled with the knowledge of God, as the waters cover the sea.'"

Kabbalah

In Kabbalah, the Zohar maintains that the seven days of the week, based on the seven days of creation, correspond to the seven millennia of creation. The seventh day of the week, the Shabbat day of rest, corresponds to the seventh millennium, the age of universal rest, or the Messianic Era. The seventh millennium begins with the year 6000 AM, and is the latest time the Messiah can come. A number of early and late Jewish scholars have written in support of this, including the Ramban, Isaac Abarbanel, Abraham Ibn Ezra, Rabbeinu Bachya, the Vilna Gaon, the Lubavitcher Rebbe, the Ramchal, Aryeh Kaplan and Rebbetzin Esther Jungreis.

Zoroastrianism

Frashokereti is the Zoroastrian doctrine of a final renovation of the universe when evil will be destroyed, and everything else will then be in perfect unity with God. The doctrinal premises are:

Good will eventually prevail over evil.
Creation, initially perfectly good, was subsequently corrupted by evil.
The world will ultimately be restored to the perfection it had at the time of creation.
The "salvation for the individual depended on the sum of thoughts, words and deeds, and there could be no intervention, whether compassionate or capricious, by any divine being to alter this". Thus each human bears the responsibility for the fate of his own soul, and simultaneously shares in the responsibility for the fate of the world.

Zoroastrian eschatology is considered one of the oldest in recorded history. The birth of its founder, Zoroaster, is unknown, with scholarly dates ranging from 500 BCE to 1,500 BCE. Pliny the Elder even suggests there were two Zoroasters. However, with beliefs paralleling and possibly predating the framework of the major Abrahamic faiths, a fully developed concept of the end of the world was not established in Zoroastrianism until 500 BCE. The Bahman Yasht describes:

At the end of thy tenth hundredth winter, the sun is more unseen and more spotted; the year, month, and day are shorter; and the earth is more barren; and the crop will not yield the seed. And men become more deceitful and more given to vile practices. They will have no gratitude. Honorable wealth will proceed to those of perverted faith. And a dark cloud makes the whole sky night, and it will rain more noxious creatures than water.

A battle between the righteous and wicked will be followed by the Frashokereti. On earth, the Saoshyant will arrive as the final savior of mankind, and bring about the resurrection of the dead. The yazatas Airyaman and Atar will melt the metal in the hills and mountains, which will flow as lava across the earth and all mankind, both the living and resurrected, will be required to wade through it. Ashavan will pass through the molten river as if it were warm milk, but the sinful will burn. It will then flow down to hell, where it will annihilate Angra Mainyu and the last vestiges of wickedness.
The righteous will partake of the parahaoma, which will confer immortality upon them. Humanity will become like the Amesha Spentas, living without food, hunger, thirst, weapons or injury. Bodies will become so light as to cast no shadow. All humanity will speak a single language, and belong to a single nation with no borders. All will share a single purpose and goal, joining with Ahura Mazda for a perpetual and divine exaltation.

Gnosticism

The Gnostic codex On the Origin of the World states that during what is called the consummation of the age, the Sun and Moon will become dark as the stars change their ordinary course. Kings will make war with each other, and thunder will cause the world to be shaken. The corrupt Archons will mourn. The sea will be troubled by fighting of the kings who became drunk from the flaming sword. Finally, great thunder will come from Sophia, the woman in the firmament above the forces of Chaos. She will cast the corrupt gods into the abyss where they will fight each other until only their chief Yaldabaoth remains and destroys himself. Next the heavens of the Archons will collapse on each other before the Earth sinks into the abyss. Light will cover the darkness and eliminate it then form into something greater than anything that ever existed before. The source of the darkness will dissolve, and the deficiency will be taken from its root. Those who were not perfected in the unconceived one will receive glories in their realms and kingdoms of the immortals, but those who were will enter a kingless realm. All will be judged according to their deeds and gnosis.

Christianity

Christian eschatology is the study concerned with the ultimate destiny of the individual soul and of the entire created order, based primarily upon biblical texts within the Old and New Testaments.
Christian eschatological research looks to study and discuss matters such as the nature of the divine and the divine nature of Jesus Christ, death and the afterlife, Heaven and Hell, the Second Coming of Jesus, the resurrection of the dead, the rapture, the Tribulation, millennialism, the end of the world, the Last Judgment, and the New Heaven and New Earth in the world to come.
Eschatological passages occur in many places in the Bible, in both the Old and the New Testaments. In the Old Testament, apocalyptic eschatology can be found notably in Isaiah 24–27, Isaiah 56–66, Joel, Zechariah 9–14 as well as in the closing chapters of Daniel, and in Ezekiel. In the New Testament, applicable passages include Matthew 24, Mark 13, the parable of "The Sheep and the Goats" and the Book of Revelation—Revelation often occupies a central place in Christian eschatology.
The Second Coming of Christ is the central event in Christian eschatology within the broader context of the fullness of the Kingdom of God. Most Christians believe that death and suffering will continue to exist until Christ's return. There are, however, various views concerning the order and significance of other eschatological events.
The Book of Revelation stands at the core of much of Christian eschatology. The study of Revelation is usually divided into four interpretative methodologies or hermeneutics:

The Futurist approach treats the Book of Revelation mostly as unfulfilled prophecy taking place in some yet undetermined future.
The Preterist approach interprets Revelation chiefly as having had prophetic fulfillment in the past, principally in the events of the first century CE.
The Historicist approach places Revelation within the context of history, identifying figures and passages in Revelation with major historical people and events. This view was commonly held by the early Christian church, then among the predecessors to Protestantism, such as John Wycliffe, Joachim of Fiore and later by the majority of Protestant Reformers, such as Martin Luther, John Calvin, and John Wesley. Further supporters of this view included Isaac Newton, among others.
The Idealist approach sees the events of Revelation as neither past nor future actualities, but as purely symbolic accounts, dealing with the ongoing struggle and ultimate triumph of good over evil.