From Halopedia, the Halo Wiki
Honorable Intentions is a song included in the Halo 3: Original Soundtrack. It plays during the level Crow's Nest. It uses the main theme of the song Enough Dead Heroes.
It starts with a low brass version of the Gregorian-style chant of the Mjolnir Mix, then swells into a resonating melody. This is dramatically replaced by drums at around 0:38. Choir then joins in with a soft melody. At 1:40, a fragmented and more minor choir melody begins, with several discordant notes being played in the background. Near the end, the song once again takes a peaceful upturn with more orchestral instruments.
It runs for 2:46.