What do Judaism, Christianity, and Islam have in common? How do they differ? How does Buddhism differ from the former three?

The key coincidence of Judaism, Christianity, and Islam is the fact that they are monotheistic religions. In the three religions, there is only one true God. They also share common doctrinal sources and ancient stories; for example, Abraham is a patriarch for the three of them. Christianity and Judaism believe in the same God, and in the Old Testament there are shared names of God. Meawhile, Islam calls God Allah.

For Islam, Jesus is a prophet recognized but he is not the ultimate prophet. This role corresponds to Muhammad, the only true Messenger of Allah, according to Islamic creed. For Christianity, Jesus is the Christ, the Messiah, the Savior, a notion with which Jews don't agree; Jews continue to wait for the arrival of the Messiah.

The main difference between the three monotheistic faiths and Buddhism evolves precisely around the existence of the figure of God. Buddhism doesn't believe in a god as it's conceived in the theologies of the 3 other faiths. There's no God in Buddhism. Relief, spiritual perfection, liberation of the soul and the mind from delusions is reached through man's own efforts to achieve that perfection.