"Cortana, all I need to know is did we lose them?" - At beginning of first Halo: Combat Evolved cutscene.
"We made a blind jump, how did they..." - Talking about the Covenant but Cortana cuts him off.
"So where do we stand?" - To Cortana.
"Well that's it then, bring the ship back up to combat alert alpha. I want everyone at their stations." - To Cortana.
"And Cortana? Let's give our old friends a warm welcome."
"Good to see you, Master Chief. Things aren't going well. Cortana did her best, but we never really had a chance." - When the Master Chief appeared on the bridge.
"Alright, I'm initiating the Cole Protocol, Article 2. We're abandoning the Autumn. That means you, too, Cortana."
"In a manner of speaking. The object we found, I'm going to try and land the Autumn on it."
"I appreciate your concern, Cortana, but it's not up to me. Protocol is clear: Destruction or capture of a shipboard AI is absolutely unacceptable, that means you're leaving the ship. Lock in a selection of emergency landing zones, upload them to my neural lace, and then sort yourself for a hard transfer." - To Cortana.
"Which is where you come in, Chief. Get Cortana off this ship. Keep her safe from the enemy. If they capture her, they'll learn everything. Force deployment, weapons research... Earth."
"Coming here was reckless. You two know better than this... thanks. Marines! Lock and load your weapons, let's be ready to move." - When Chief opened the prison cells.
"While the Covenant had us locked up in here, I overheard the guards talking about this ring world. They call it... Halo."
"Whoever controls Halo controls the fate of the Universe."
"That's bad news. If Halo is a weapon, and the Covenant gain control of it, they'll use it against us and wipe out the entire Human race. Chief, Cortana. I have a new mission for you. We need to beat the Covenant to Halo's Control Room. Marines! Let's move!" - Preparing to leave the brig.
"Stow the bellyaching, soldier. Remember, you're a leatherneck. Cortana, if you and the Chief can get us into one of those Covenant dropships, I can fly us outta here." - When Echo 419 couldn't extract Captain Keyes, Master Chief and the other Marines from the Truth and Reconciliation.
"Understood. We're still en route to the objective. I may be out of contact when we get there. Here are your orders: I want you to use any means necessary to force your way into the facility and find Halo's Control Center. We have to get to the Center before the Covenant. And failure, people, is not an option." - O.S.
"Chief... don't be a fool, leave me!" - O.S., to the Master Chief, on the Keyes level.
"I gave you an order, soldier! Now pull out!" - O.S., with pain.