What similaritys do Jews and christians have?

Answer 1

Both believe in one, all-powerful, personal, loving, saving God. Both believe in the existence of a Messiah. Both have (in general) sophistocated cultures. Both respect the Jewish scriptures as sacred texts. Both see Israel as a holy land. Both believe that faith is important. Both believe that God has sent prophets to the earth in the past. Both believe that there is a happy afterlife for at least some people. Both have holy books. Both have populations in Europe, Israel, and the USA (Christianity also has populations in many other places). Both are divided into more conservative groups, who are adamant that reverence is important, and more liberal groups, who are more lenient about the importance of acts of reverence. Both have the general viewpoint (with exceptions) that God wants us to be good people on earth, to promote social justice, to love one another, and to love God. Both accept (with exceptions) that it is not necessary to completely rid ourselves of the fruits of this earth, but that we must make certain sacrifices in order to be better people. (Christianity is somewhat more focused on the rejection of the fruits of the earth, while Judaism is somewhat more focused on the idea that we can both enjoy the God-given fruits of the earth and be good people.)

Correction:

The Christian concept of messiah does not exist in Judaism.

Judaism is not faith based, it's act based. This means that faith is meaningless if your actions don't support your claimed beliefs from the Jewish perspective.

Answer 2

They both follow the teachings of the Old Testament