Righteous Non-Jews - Chasidei Ummot HaOlam
Judaism has never taught that one has to be Jewish in order to be saved.  In contrast to medieval Christianity, which held that there was no salvation outside of the Church, the rabbis believed that "The righteous of the nations of the world have a portion in the world to come" (Tosefta Sanhedrin 13-2).
The rabbis of the Talmud had a high regard for righteous non-Jews, and even held them up on occasion as moral exemplars.  A certain man, Dama ben Netina, was known for being particularly scrupulous in honoring his parents:  "Our rabbis say that some of our wise men came to him to buy a precious stone in place of one which had fallen out, and been lost, from the breastplate of the High Priest... They agreed with him to give a thousand gold pieces for the stone.  He went in, and found his father asleep with his leg stretched out on the box which contained the jewel.  He would not disturb him, and came back without it.  When the wise men perceived this, they thought that he wanted more money, and they offered him ten thousand gold pieces.  When his father woke up, he went in, and brought out the jewel.  The wise men offered him the ten thousand pieces, but he replied:  'Far be it from me to make a profit from honoring my father; I will take only the thousand which we had agreed on'" (Devarim Rabbah 1:15).
Whereas Jews are considered bound by the 613 laws of the Torah, Judaism demands from non-Jews fulfillment only of the Seven Noachide Laws, modeled on the quintessentially ethical non-Jew Noach (see Noach and Seven Noachide Laws).
In recent years, the term chasidei ummot ha-olam has become associated with European non-Jews who risked their lives during WWII to save Jews from the Nazis.  At Yad Vashem, the Jerusalem museum set up to commemorate the Holocaust, a grove of trees has been planted to honor these heroes (see Righteous Gentiles).
To this day, it is not uncommon to hear traditional Jews refer to a non-Jewish friend of the Jews as "one of the chasidei ummot ha-olam" - literally, "one of the righteous of the nations of the world."  The Zohar, the major work of Jewish mysticism, states that all non-Jews who do not hate Jews and treat them justly are chasidei ummot ha-olam (Shemot 268a).
While many Jews are knowledgeable about the history of anti-Semitism, fewer are aware of the smaller, but vital, tradition of philo-Semitism, whose adherents are the chasidei ummot ha-olam who have worked on behalf of Jews and ethical causes.