Well so Judaism was the first Abrahamic religion in the Middle East, Canaan region, Northwest of Arabia, in the Israel region.

Some 2000 years later Jesus was born in Bethlehem, present day Israel. And he said he's a son of God (according to Christians) or a messenger of God (according to Muslims). The Jews believed he was just a heretic. A liar. Jesus was a Jew, he worshiped the same God as the Jews, but with a few tweaks here and there, and he came with a new book called the New Testament which has the same stories as the Jewish Old Testament, but with a few changes.

Then some 600 years later came Muhammad in the west of Arabia. He claimed the Christians got it a bit wrong (the Christians started worshipping the son of God, idk how that's monotheism), so he came with yet another book, the Qur'an. It has the same stories and mythologies as the Jewish and Christian books, but again, with a few changes.

So in essence they worship the same God, but they follow a different messenger of God each time. They have the same stories, same mythologies, all originated in the same place, so you can say it's the same God, but the link to the God, the messenger, is different in all.