"You are one of our most treasured instruments. Long have you led your fleet with honor and distinction. But your inability to safeguard Halo was a colossal failure."
—Prophet of Truth, in the level "The Heretic"
"Chief, get inside, gear up. We're taking this fight to the surface"
—Commander Keyes, in the level "Cairo Station"
""Regret is a name, Sergeant. The name of one of the Covenant's religious leaders. A Prophet. He's on that carrier, and he's calling for help."
—Cortana, in the level "Outskirts
"I've been analyzing the Covenant tactical chatter. They're surprised, confused... I don't think they expected us to be here. Not you and me...all of us...humanity, on Earth. Odd, I know, but it does help explain why they came here in such small numbers."
—Cortana, in the level "Outskirts"
"Oh, I know what the ladies like."
—Sergeant Johnson, in the level "Metropolis"
"The Taming of the Hunters, the Grunt Rebellion - were it not for the Arbiters, the Covenant would have broken long ago!"
—Prophet of Mercy, in the level "The Arbiter"
"Halo's destruction was your error, and you rightly bear the blame. But the Council was... overzealous. We know you are no heretic. This is the true face of heresy, one who would subvert our faith and incite rebellion against the High Council."
—Prophet of Truth, in the level "The Arbiter"
"The Elites are blind, Arbiter ... but I (holds up two Holodrones) ... will make them see."
—Sesa 'Refumee, in the level "The Oracle"
"In a gesture of peace and reconciliation, the Prophets promised to find the means of the Forerunners' transcendence, and to share this knowledge with the Elites. The Elites promised to defend the Prophets as they searched. A simple arrangement, that has become our binding Covenant!"
—Hologram of the Prophet of Regret, in the level "Delta Halo"
"This is not your grave... But you are welcome in it."
—Gravemind, in the level "Regret"
"The parasite is not to be trifled with. I hope you know what you are doing."
—Rtas 'Vadumee, in the level "Quarantine Zone
"You will search one likely spot, and you will search another. Fate had us meet as foes, but this ring will make us...brothers."
—Gravemind, in the level "Gravemind"
"I knew the Covenant were good at re-purposing Forerunner technology, but this is amazing... They've been using the Forerunner ship's engines as an energy source for the city. The ship isn't so much launching as it is disengaging; uncoupling itself from High Charity's power grid - Stopping Truth, that's all that matters!"
—Cortana, in the level "High Charity"
"Tartarus. The Prophets have betrayed us."
—The Arbiter, in the level "The Great Journey
...And we can not forget the Cliffhanger:
"Sir. Finishing this fight."
—Master Chief, in the level "The Great Journey"