Here is the Great Force War Side Mission entry.
-- Log 1 --
To win this war we Jedi must make sacrifices. We must ask of our young what we once would only ask of the elders. The Jedi Order needs Knights, but we will not forsake our traditions to boost our ranks. The Trials are still an essential part to your life. Good luck to you all.
-- End log --
To pass the Trial of the Spirit, apprentices had to look deep within their souls, on a quest of self-discovery. This test was designed to pit a potential Knight against their most dangerous enemy: the darkness within themselves. Because of this grueling self-examination, this Trials was often known as Facing the Mirror. (note: I got all this information from Wookiepedia).