Answer:
All three faiths emphasize their special covenant with God, for Judaism through Moses, Christianity through Jesus, and Islam through Muhammad. Christianity accepts God's covenant with and revelation to the Jews but traditionally has seen itself as superseding Judaism with the coming of Jesus.
The real difference between the two religions, however, lies in their basis for belief. Judaism is based on the unique historical event of a divine revelation experienced by the entire nation. Whereas Islam is based on the prophetic claims of a single individual who subsequently convinced others to follow his ways.
Recognizing the inherent limitations of speaking for another faith tradition, we can say that Judaism and Islam differ primarily from Christianity in an understanding of the person of Jesus. For Christians, Jesus is the fulfillment of the Old Testament promise. Judaism and Islam simply do not recognize the divinity of Jesus. For this reason, the monotheism practiced by Judaism and Islam is different from the monotheism of Christianity. Christianity has a Trinitarian understanding of the one true God because of Jesus’ divinity that is not shared by Judaism and Islam. In fact, Islam would describe Christianity as a tri-theist religion, rather than a monotheistic religion.