Christianity originated in southwest Asia, taking root in the regions of modern-day Israel, Palestine, Syria and northern Egypt. There are few source materials prior to the year 325 A.D.; thus the precise origins and nature of early Christianity remain unclear. Christian Scripture describes the religion as a Christ-centered fulfillment of Jewish messianic prophecy, and as a radical re-alignment of the Jewish community with its principal moral and ritual laws (or commandments).
Scriptural and oral traditions describe Jesus and his followers as assertively Jewish; a band of zealots determined to “set right” the moral fiber of the Jewish community and to free it from the impure influences of the Roman Crown. In this depiction, early Christians were motivated by a desire to bring religious and moral cohesion to the Jewish community, not to separate themselves from Judaism.
However, a close read of the Christian Gospels reveals the fundamentally radical nature of the teachings of early Christianity. Jesus preaches a doctrine of universal acceptance in which all persons shared in the favor and grace of God. This doctrine stands in stark contrast to the orthodox conception in which Jewish persons have access to “special favor” in the eyes of God. These issues of theology remained a source of conflict and persecution until well into the medieval period and beyond. The violence and terror of Spanish Inquisition, the Protestant Reformation, and the Crusades were all, at least in part, rooted in such issues.
Islam shares this pattern of moving from a tribal orientation to a more universal orientation. The religion was born in the Arabian Desert, approximately 500 years after the birth of Christianity. Like the Christians before them, early Muslims struggled to identify themselves relative the religious communities from which they sprang. Scriptures and early oral histories describe Islam as a corrective measure to the Jewish and Christian traditions.
Early Muslims found themselves ostracized from their home clans so much that eventually they disbanded from their native lands and settled in the city of Medina. In Medina, their concentrated numbers and relative safety allowed them to construct a religious community life that facilitated strong personal ties and religious identity. This community (or "ummah") became an iconic religious model of how Islamic community should look. Many Islamic practices, governing everything from domestic life to commerce, are drawn from this model Medina ummah.
Both Christianity and Islam spread in part by conquest and in part by conversion. These religious movements represent a fundamental shift away from tribal, local deities and perspectives toward more universal deities and perspectives. In practice, these new religious expressions also facilitated greater communication and interaction with “outsiders,” as zealots spread their message to neighbors and learned to assert their unique religious identities in cosmopolitan, religious diverse environments. The rise of monotheism is associated with increased trade, mobility, conquest, empire, and other forms of contact. Each of these traditions reflects the ways in which monotheism has served as a catalyst for cultural change and cross-cultural contact throughout human history.
Judaism Christianity and Islam are said to be the three monothestic religions, and they are deeply related to one another.
The story of how each of these three arose, its early forms, its challenges, its crimes; these are the subjects of encyclpedias and history books.
I am not sure how your teacher wants you to sum up or encapsulate these monumental and very diverse stories.
There are just so many wonderful questions of history and theology to explore within this range of material. So interesting!