The question of Abraham is a difficult one because on the one hand, it’s become an important figure that helps Muslims, Christians, and Jews to recognize certain commonalities among them and also, certain shared heritage, this common interest in one principal, religious figure.
On the other hand, from an academic point of view, we notice there are real differences in the view about Abraham. For example, for Muslims, Abraham is not the first monotheist or the founder of Islam. A Muslim would say the first monotheist, the first Muslim was Adam. So, the first man whom God created was created as a Muslim; and he preached Islam. He didn’t have a big audience to preach it to, but he preached Islam, as did figures after him, including Noah and Abraham as well.
For Jews too, of course, the figure of Abraham has a principal role but maybe not necessarily as the founder of Judaism in any way or the founder of monotheism. Jews, of course, look not to Abraham but to his grandson, Jacob, who has the name Israel later as the founder of the people of Israel.
And, we might even notice that in theological terms, the person of Abraham becomes an object, in some ways, of disagreement and, also, methods of expressing a particular theological viewpoint. For example, in the Qur’an, the Qur’an tells us explicitly in the third chapter that Abraham was neither a Jew nor a Christian but a Muslim. And, the Qur’an, indeed, seems to hold Abraham up as a, sort of, prototypical figure of a Muslim who is distinct from Judaism and Christianity. The Qur’an even says, and correctly so, that the Torah given to Moses and the Gospel given to Jesus came after Abraham.
If we notice in the New Testament, Paul, in the Book of Romans, looks to Abraham in a very particular way, very Christian way, as an example of faith. So, unlike those who were justified under the law given to Moses, Abraham who lived before Moses, then before the law, was justified by his faith because God gave him a promise which seemed to have been unbelievable; and Abraham believed in that promise and his belief was counted unto him as righteousness.
So, from an academic point of view, we have this really, intriguing perspectives that we find in the three traditions on Abraham. All of the traditions use Abraham in a particular way and, at the same time, as believers of different traditions, Muslims, Christians, and Jews, have found Abraham as a figure who can allow them to reflect on commonalities in the faith.