We've got to believe in something 3

 is a track in Xenosaga II to III: A Missing Year. It is a version (without the main melody) of the second part of we've got to believe in something from the Xenosaga III: Also Sprach Zarathustra Original Sound Best Tracks, along with, , and

It plays when Shion discusses Almadel, Lemegeton, and Grimoire in Chapter 2.