Why does Christianity agree with Judaism to some degree but they both disagree with Islam although they all believe in God and all messengers or prophets regardless of the disputes between them?

All Theists believe in some god or higher power… Atheists do not. Christendom, Judaism, and Islam all have divisions within themselves yet retain core beliefs specific to their religion. The principle of good vs. bad is not owned by any one group but is something within all people, even Atheists. Per the God of the Bible, the Israelites were a chosen people who the Bible tells us, were largely unfaithful to their God, often following the practices of Pagan deities. They rejected the Son of God and had him put to death. The Christian religion was built upon a simplified version of the Laws God gave to Moses (retaining them in principle) and the new chosen people were to learn from the mistakes of the first covenant people who God himself eventually put aside. The Islam religion began approximately 600 years after Jesus' death through a man named Muhammad. The ancient prophets (Israelites) led to the coming Messiah, of which Christians believe Jesus was. The Jews rejected him as their Messiah.