Here is a brief overview of Islam from the ESV Study Bible:"Islam, the second largest religion in the world after Christianity, is found not only in the Middle East but throughout Asia, Africa, Europe, and North America. (See also The Bible and Islam.) Although historically discussion of Islam begins with Muhammad (c. a.d. 570–632), Muslims insist that Islam is God's eternal religion for all humankind and that Muhammad was simply the last and greatest in a long line of prophets. Born in Mecca, an important trading center in the Arabian peninsula, Muhammad was an orphan by age six and was reared by his grandfather and uncle. At age 25 Muhammad married a wealthy widow named Khadija, and he became engaged in various business ventures.
The Arabs of Mecca were largely animists and polytheists, although there were Jewish and Christian influences in the area. Living in Mecca, Muhammad was troubled by the polytheism and superstition all around him. Around the year 610 he began to have experiences that he took to be revelations from Allah, the one true God. Convinced that he had been called to be a "Messenger of God," Muhammad continued to receive revelations supposedly dictated by the angel Gabriel over a 20-year period. The revelations were memorized by Muhammad's followers and were eventually written and codified in the Qur'an, which is understood to be the Word of God. Muhammad regarded himself as being in continuity with prophets of the OT and Jesus. He claimed to be restoring the original revelation of God that Jews and Christians had corrupted.
But Muhammad met stiff resistance to his message in Mecca, and in 622 he and his followers moved to Medina (in western Saudi Arabia). Under Muhammad's leadership, Medina was transformed into an Islamic theocracy, and the social and religious patterns of Medina are regarded as an ideal for Islamic societies. In 630 Muhammad returned to Mecca, captured it, and began transforming the city. Then suddenly, in 632, at about 62 years of age, Muhammad died.
Questions about the legitimate successors to Muhammad resulted in the two major divisions within Islam. Sunni Islam, comprising roughly 85 percent of Muslims today, recognized caliphs (Islamic leaders) not necessarily related to Muhammad as his legitimate successors. Shi'a Islam, comprising 10 to 15 percent of Muslims, insisted that legitimate successors must descend directly from Muhammad and that Ali (Muhammad's son-in-law, who was martyred) and his sons were the rightful heirs to leadership.
Both branches of Islam embrace a strict monotheism. Islam calls for acknowledgment of the incomparable greatness of Allah and submission to his sovereign will in all of life. Allah is the eternal creator who sovereignly rules over nature and the affairs of humankind.
The religious, intellectual, and social life of devout Muslims is structured around the "Five Pillars": (1) the Shahada, or "witness" of the basic creed of Islam ("I bear witness that there is no god but Allah, and that Muhammad is the prophet of Allah"); (2) prayer; (3) fasting; (4) almsgiving; and (5) the pilgrimage to Mecca.
Islam teaches that the present world will one day be destroyed by Allah and that all humankind, past and present, will then be raised to face divine judgment. Human beings have a weakness of will and a tendency toward sin. Although humans are tempted by Iblis (the devil), it is within their power to resist and remain faithful to the will of Allah. In the judgment, each person's deeds will be impartially weighed in the balance. Salvation is strictly on the basis of submission to Allah and faithful adherence to the teachings of Islam. Some will be admitted to Paradise, others consigned to Hell.
Jesus is mentioned frequently in the Qur'an. He is called the Messiah, Son of Mary, Messenger, Prophet, Servant, Word, and Spirit of God. Jesus is portrayed as a great miracle worker and one of the greatest of the prophets. The virgin conception of Jesus is affirmed in the Qur'an.
But the Qur'an omits Jesus' teachings as contained in the Gospels and provides no narrative description of his ministry. The Qur'an depicts Jesus as explicitly disclaiming deity (5:109–119) and includes numerous denunciations of what seem to have been views that were common in Muhammad's lifetime regarding the Christian doctrines of the incarnation and the Trinity (cf. 4:171; 5:17; 9:30–31). Although a great prophet of God, Jesus is said to have been in no sense divine. Particularly offensive is the Christian title "Son of God," which is understood by Muslims as referring to physical generation. "Never has Allah begotten a son, nor is there any other god besides Him" (23:93). Muhammad seems to have thought of the Trinity as consisting of the Father, the Virgin Mary, and their child, Jesus.
Traditionally, most Muslims have believed that Jesus was not crucified. Surah 4:155–159 denies that Jesus was in fact killed on the cross. A widely accepted interpretation of this text has been that the Jews tried to kill Jesus but were unable to do so, and that God rescued him and carried him away to a safe place in the heavens. Islam denies the need for a Savior and the substitutionary atonement. The Qur'an states that "no soul shall bear another's burden and that each man shall be judged by his own labors" (53:38). Salvation is by works. "On that day no soul shall suffer the least injustice. You shall be rewarded according only to your deeds" (36:54)."