Understanding Monotheism in Judaism, Christianity, and Islam

Monotheism is about worshipping only one God while denying the existence of other gods. What do the major monotheistic religions believe?

Jul 11, 2022By Tendai Kashiri, BA Theology
christ fairchild exodus scroll
Face of God, by Mary Fairchild, 2019, June 25, via LearnReligons.com


The three major monotheistic religions of the world are Christianity, Judaism, and Islam which share a lot of commonalities. They all believe in God the creator, one who rules the universe, judges, punishes, and also forgives. They are referred to as Abrahamic faiths because they share the same father of the faith, Abraham. The monotheistic deities are considered omniscient and omnipotent. They are incomprehensible, hence they cannot be depicted in any form.


Monotheism in Judaism

exodus scroll monotheism
Exodus Scroll Scaled-Biblical Manuscripts, by Solomon Schechter, 1892, via Houston Baptist University


Judaism is the world’s oldest monotheistic religion dating back nearly 4,000 years. Their belief is that the one God revealed Himself through ancient prophets. The first prophet he revealed himself to was Abraham who is now known as the founder of Judaism.


Abraham became the father of the faith, the foundation, and link to the three monotheistic religions, Judaism, Christianity, and Islam. These religions all uphold Abraham as the father of faith and believe in fasting as a way to purify oneself and get closer to God.


God chose one man to work with, Abraham. Through the family of Abraham, He created a nation that he could teach his commandments to and who he could give a culture to live by. Abraham had Isaac, and Isaac had Esau and Jacob. Jacob had twelve sons from whom God built the 12 tribes of Israel and they created a God-centered culture. The Jewish culture was a system whereby the Israelites worshipped one God, trusted in him, and offered sacrifices to and depended on him.


abraham sacrifice monotheism
Lehi Offers Sacrifice in the Wilderness, 2016, via Brigham Young University

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The sacrificial system is at the center of the three monotheistic religions. They all follow the documented story of Abraham and how he was tested and proved his faithfulness to God. He was asked to sacrifice his only son to God and he obeyed. Just as he was about to sacrifice his son, God stopped him and provided him with a ram to sacrifice. His story is about the ultimate sacrifice and obedience to God.


The Jewish people’s hope is pinned on a promised messiah. Their God, known as YHWH, promised them a messiah who would be their liberator, a righteous savior who would rule and judge them, and the whole world.


rabbi in study monotheism
A Rabbi Scholar in His Study, by Julius Fehr, 1860-1900, German, via Christie’s


The Jewish people’s places of worship are called synagogues. This is where the spiritual leaders also called rabbis teach scripture with an emphasis on monotheism. The teachings are from a sacred text called Tanakh or the Hebrew Bible which includes the Old Testament books (which is also in the Christian Bible in a different order).


Jewish monotheism stands out because it was unique in the ancient world. Most ancient societies such as the Greeks, the Egyptians, and the Romans were polytheistic, that is, they believed in and worshipped multiple gods. One of Judaism’s strongholds is the belief that the Jews have a special covenant or agreement with God. They are the chosen people of God. They follow God’s commandments and laws and exclusively worship Him. Monotheism was such a high priority, that failure to practice it and worshipping other gods resulted in the Israelites being punished by YHWH.



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Christ Carrying the Cross, by El Greco (Domenikos Theotokopoulos), ca. 1577-87, Greek, via Metropolitan Museum of Art


Christianity was birthed from Judaism. Christian scripture includes the Jewish scriptures, referred to as the Old Testament. The Old Testament is a foreshadowing of the New Testament. Jesus is the fulfillment of all the messianic prophecies in the Old Testament. Judaism ends in the Old Testament but, Christianity continues from the Old Testament to the New Testament.


In the New Testament, the Jewish Sacrificial system is still fully functioning up until Jesus Christ is crucified and he becomes the final ultimate sacrifice that takes away the sin of the world permanently. In Christianity, the Jewish sacrificial system and laws are all fulfilled in Jesus’ death on the cross.


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Head of Christ Crowned with Thorns, After Guido Reni, 1640-1749, via National Gallery


The New Testament comprises of Jesus’ teachings, his disciples and followers’ writings. The Jews are still waiting on their promised Messiah but in Christianity, the promised Messiah came 2,000 years ago but the Jews rejected him.


Monotheism is important to Christianity. The Christians believe in one God, but this God is three in one, also referred to as the Trinity. The trinity has been a controversial subject which has created arguments that the Christians actually have three gods, and are thus not practicing monotheism.


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Holy Trinity, by Casper de Grayer, 17th Century, via MutualArt


The members of the Trinity are God (YHWH), Jesus (the son of God), and the Holy Spirit (who is the spirit of God). The triune God is a stumbling block to many because it is unfathomable for many people to believe in a God who is supposedly one but also is three distinct individuals.


If monotheism is a belief in one God, how can Christianity be called a monotheistic religion when it seems as though the Gods are three? The Trinity simplified is, three persons unified in one Godhead.


It is rooted in the idea that God came to meet the human race in a threefold figure as the father (creator), the Lord Jesus Christ who lived among human beings and as the Holy Spirit who is the helper in a Christian’s life. Therefore it is clear that Christians practice exclusive monotheism. Failure to do so could yield the same results as when the Jewish people disobeyed God and looked to foreign gods — losing the protection of God in one’s life which leads to a life full of misfortunes.


Monotheism and Islam

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Digital Exhibition of the Birmingham Quran Manuscript, ca. 568 and 645, via the Washington Post


Islam is also an Abrahamic monotheistic religion. The word Islam means submission to the will of God. Muslims worship an all-knowing God who is called Allah. Muslims believe that Muhammad is the messenger of God.


They believe that Allah’s word was revealed to the prophet Muhammad through the angel Gabriel. Several prophets were sent to teach Allah’s law. Some of the Muslim prophets are the same as those of the Jews and Christians such as Abraham, Moses, Noah, David, and Jesus.


The Muslims also have a sacrificial system. Sacrifice is an important concept in Islam, as it is in Judaism, and Christianity through the final sacrifice of Jesus Christ. Eid-al-Adha or the Festival of Sacrifice (the second major Islamic holiday which falls on the tenth day of the month after the pilgrimage) is when Muslims offer sacrifices to Allah. During this period animals are sacrificed, usually lambs or goats.


There is no intermediary in Islam, instead, Muslims have a direct relationship with God. Their prayer, also known as salat is ritual worship which is done five times a day at dawn, noon, late afternoon, sunset and night.


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Muslims at Prayer, by Ulet Ifansasti, 2018, via History.com


According to United Religious Initiative, the six major beliefs of Islam which are rooted in monotheism are:


  • They believe in one God who is Allah.
  • They believe in angels.
  • They believe in the holy books. The Torah was revealed to the prophet Abraham. The Bible revealed to the prophet Jesus. The Quran (Koran) was revealed to the prophet Muhammad.
  • They believe in the prophets sent by God: Noah, Abraham, Ishmael, Isaac, Jacob, Moses, Jesus and Muhammad.
  • They believe in the day of judgement after death.
  • They believe in the divine decree which states that God is all-powerful and nothing happens without his permission. However, God has given human beings free will to choose between good and evil. In the end, human beings will be held accountable for their lives.


studying koran osman hamdi bey
Man Reading Koran, by Osman Hamdi Bey, 2019, via TallengeStore.com


The Abrahamic faiths no doubt practice strict monotheism. They have so many similarities but, their one unifying commonality is the belief in one God. The differences have a significant impact on their major doctrines. The Christian doctrine hinges on Jesus Christ as the Son of God, the promised Messiah, and yet in Islam Jesus is an ordinary prophet.


In Judaism and Christianity, Ishmael is not considered a prophet. He is considered  Abraham’s illegitimate son. He has no place in the history of God’s chosen people. However, in Islam, he is given a high position as a prophet.


Being united under monotheism, Judaism, Christianity, and Islam seem to have branched off the same tree but they differ in their major beliefs. The sacrificial system no longer exists in the Christian and Jewish world and yet it is alive in Islam.


three religions cartoon
Judaism, Christianity, and Islam Interfaith Relations, by Asher Maoz, 2017, via UEFA


Although monotheism is associated with the three Abrahamic faiths, it is older than them. An Egyptian pharaoh named Akhenaten tried to establish monotheism during his reign. He advocated for the worship of one God whose name was Aten, the sun god, and he made himself the one who communicated with this God. The religion was called Atenism. Although not as popular as Judaism, Christianity, and Islam, Atenism existed in Egypt when Akhenaten was a pharaoh in 1341 BCE.


Thea Baldrick (2022) explains that his introduction to monotheism might have been due to a fear of a plague that was ravaging and killing Egyptians. Whatever the reason for Atenism’s unpopularity, one cannot deny the revolutionary and forward-thinking nature of Akhenaten’s religion.


All three Abrahamic faiths preach kindness to humanity and peace. Having similar concepts should not mislead anyone into thinking that they are the same. On the contrary, the differences are unmistakeably huge.

Author Image

By Tendai KashiriBA TheologyTendai is a Theologian who loves simplifying Christian doctrines so that everyone can understand the Gospel. Fascinated by the power the entertainment industry has on people, I express the simplicity of the Gospel through writing and recording gospel music. As an upcoming Gospel artist, reaching people with the Gospel in melody opens up interactions with people from different cultural backgrounds. I see the Gospel explained in different cultures. This fuels my passion to write about the Christian Gospel that transcends culture, race and age.