Christianity, Judaism, and Islam are referred to as the “Abrahamic” religions because they are all rooted in a common ancestor – the biblical Abraham.
Today is like an alignment of planets because the three main Abrahamic religions are celebrating three important holidays at the same time: Ramadan, Passover, and Easter. I was thinking it would a good day to remind ourselves what the three faiths have in common, so I did an internet search and found information at the British Library.
The library had put the question in the hands of Anna Sapir Abulafia, Professor of the Study of the Abrahamic Religions at the Faculty of Theology and Religion at the University of Oxford and a Fellow of Lady Margaret Hall.
She writes, “When people refer to the Abrahamic religions they are usually thinking of Judaism, Christianity and Islam. There are, in fact, more Abrahamic religions, such as the Baha’i Faith, Yezidi, Druze, Samaritan and Rastafari, but this article will focus on the main three aforementioned.
“The term ‘Abrahamic’ highlights the hugely important role which the figure of Abraham plays in each of these traditions. Jews, Christians and Muslims look to their sacred texts to find the history of Abraham and how it has been interpreted through the ages. For Jews, the central text is the Hebrew Bible consisting of the Torah (the first five books or Pentateuch), the Prophets (Nevi’im) and the Writings (Ketuvim). Abraham’s story unfolds in Genesis, the first book of the Torah. …
“For Christians, the Hebrew Bible is the Old Testament, the precursor of the New Testament that narrates the birth, ministry, death and Resurrection of Jesus Christ as well as the life and preaching of the earliest followers of Jesus. For Christian understandings of Abraham the Letters of St Paul are of particular importance.
“Muslims engage with the figure of Abraham/Ibrāhīm in their holy book, the Qur’an, as well as in the Hadith, the body of writings which transmit the sayings and actions of the Prophet Muhammad.
“Let us turn to Genesis to map out the story of Abraham, which is shared by Jews and Christians. In Genesis 12: 1–3 Abraham (at that stage his name is still Abram) is called by God to: ‘Go from your country and your kindred and your father’s house to the land that I will show you. I will make of you a great nation, and I will bless you, and make your name great, so that you will be a blessing … and in you all the families of the earth shall be blessed.’ “
Professor Abulafia proceeds to describe in detail how each of the religious traditions perceives Abraham. She explains that Abraham has a son with Hagar (Ishmael) and also with Sarah (Isaac), saying, “trouble brews between Sarah and Hagar as their sons grow up, and Sarah persuades Abraham to send Hagar and Ishmael away (Genesis 21). God promises Hagar that Ishmael too will be made into a great nation.
“God then tests Abraham’s faith by commanding him to sacrifice Isaac (Genesis 22). But when Abraham is about to sacrifice Isaac on Mount Moriah, an angel stops him and directs his gaze to a ram caught in the thicket. The ram is sacrificed instead of Isaac. …
“In Jewish tradition, Abraham became identified as the ‘first Jew.’ He is depicted as the embodiment of the faithful Jew upholding God’s commandments. Traditionally, Jews see themselves as the descendants of Abraham through his son Isaac and Jacob, his grandson. …
“In Christian tradition, Abraham’s faith became paradigmatic for all those who followed Jesus. In the words of St Paul, in Romans 4: ‘For what does the scripture say? “Abraham believed God, and it was reckoned to him as righteousness.” ‘ …
“Islam shares with Judaism the narrative of Abraham’s destruction of idols in the service of the worship of the one true God. In Surah 37 of the Qur’an, Abraham ‘said to his father and to his people, “What is that which ye worship? Is it a falsehood – gods other than Allah that ye desire? Then what is your idea about the Lord of the worlds?” … Then did he turn upon them, striking (them) with the right hand. … He said: “Worship ye that which ye have (yourselves) carved? But Allah has created you and your handwork!” ‘ …
“In the same Surah, Abraham has a vision that he must sacrifice his son. As in the Bible, Allah intervenes in time. The Qur’an emphasizes that this was a difficult trial which both Abraham and his son passed with flying colors. It does not specify whether the son was Isaac or Ishmael, although today most Muslims believe that it was Ishmael/Ismā‘īl.
“The biblical narrative concerning the dismissal of Hagar and Ishmael is paralleled in the Muslim tradition with Abraham taking Hagar and Ishmael to Mecca, where in due course Abraham and Ishmael build the Ka‘bah, the focus of the Hajj.” More from the professor here.
I wrote another post in 2011, here, on the Abrahamic faiths. In a 2014 post, I described a nonprofit that brings together young people from the three backgrounds. A post earlier this year was on an Abrahamic collaboration that is helping Afghan refugees in Maryland, here.
Suzanne's Mom's Blog 
I grew up Catholic and was surprised at the amount of overlap and shared history between the three religions. It’s like we have a common DNA.
So glad to know you’ve noticed that.
Yes, a common DNA!
I appreciate that you look at comments, too. Milford Street always has good ones.