"You know I oppose your mission, but you're exceeding its parameters anyway. You've put yourself in jeopardy. You've done enough. If you will not come to me, I will find my way to you." - One of the Didact's messages to the Librarian.
"No. Activation is murder. A genocide larger than [this galaxy] has ever known. We are sworn to protect life not destroy it! That is the Mantle we were given to carry." - A response to the Librarian's plea to activate the Halo Array.
"The Mantle has not failed! I've already razed scores of worlds - sterilized systems, routed and [disintegrated] the parasite! We're learning its tricks and strategies. We can halt this thing! And we can follow in Their footsteps! There are no unstoppable forces in this universe. There are no immovable objects. Everything gives if you push hard enough." - The Didact insists that the Flood can be defeated in another message to the Librarian.
"We've confirmed your observations. Infected supraluminal ships are arrowing inward from several clusters. No more spiral growth. The thing is counterattacking. Suppression, Security and Emergency Circumstance fleets are all being recalled. Systems are evacuating. Mendicant Bias is no longer communicating with us. But now I can guess where you are." - The Didact responding to one of the Librarian's final transmissions as the Flood's collective forces, led by a rampant Mendicant Bias, bear on the Maginot Sphere.
"Proud? When I have failed you utterly, how can I feel anything but sorrow?
Bias has come undone. He crossed the line this morning - brought the abomination with him - and destroyed your waiting rescue party.
It's over. We're activating the [destructive arrayed matrix], our shameful last resort. I can picture you in your garden, surveying all you have created - surveying all you have preserved. And I curse the circumstance that keeps my finger on the trigger.
Of all the fates to befall us, this is the cruelest of all. My inaction and hesitation and foolishness kept me here, on the wrong side of the line. And [300 years[?]] of our society's failure and miscalculation makes me your executioner. It's too much to bear.
Mendicant Bias is trying to prevent us from firing the Array. He speeds back to the Ark, but he won't succeed. Offensive Bias will stop him, and I will burn this stinking menace in your name.
I will begin our Great Journey without you, carrying this bitter record. Those who came after will know what we bought with this [false transcendence] - what you bought, and the price you paid." - The Didact's final transmission to the Librarian before activating the Halo Array.
"Beggar after knowledge. Mendicant Bias. That is the name I gave you when last we met. Do you remember the moment of your inception? The moment I connected you to the Domain and you were ceded control of all Forerunner defenses?" - The IsoDidact as he prepares to deactivate Mendicant Bias.
"Poor machine. Poor, poor machine. Your time here is done." - before he shuts down Mendicant Bias.
"Sickness, slavery, lingering death! We will analyze everything here, and we will learn. The Flood will be defeated." - Bornstellar Didact, defying the Primordial's assertions that the Forerunners will eventually submit to the Flood.
"Let your life race ahead. You were made to survive deep time, but now it will arrive all at once. No sweetness, no more lies! Let a billion years pass in endless silence and isolation..." - Bornstellar-Didact as he executes the Primordial by activating its stasis chamber.
"No answer! Again and yet again—never an answer!" - after killing the Primordial.
"Nothing is decided. This isn't over. It will never be over." - refusing to give up after the Primordial renders judgment on the Forerunners.
"No longer a Promethean. No longer a Warrior-Servant. A traitor!" - The IsoDidact responding to the Ur-Didact using a Composer on Omega Halo, and then deserting the Forerunners.
"I send you on your way, friend. Your new home will be Installation 04. I also give you a new designation. Henceforth, you will no longer be just a guide and assistant. You will be guardian and protector of an entire installation. You will be called 343 Guilty Spark."
"You've traveled a long ways with me, old friend. We were young and foolish when we met. So much has happened for both of us. We are not at all what we were, are we?"
"Now, old friend, we have the most important job in history-perhaps in all time. You may very well outlast all of us here. You may see the new galaxy emerge. Tell me Chakas, if it was your choice, after all we have seen and survived... would you fire the rings?"
"Forgive us." - The IsoDidact before activating the Halo Array.
"In the end the choice was mine alone, and I would do it again, my old friend."
"Ancilla 05032 of the designation Mendicant Bias, you have colluded with the greatest enemy of the Mantle."
"You are brought here to be sentenced. You have not been immediately destroyed because you may yet be needed. Your intinmate knowledge of the Flood makes you valuable should they return, but we can never trust you, never again allow you any latitude. You will be entombed here. Your processes locked, frozen into a single thought for all eternity: absolution. Should you be needed you will be reawakened, should there be no need you will be buried here until the end of living time."
"All I know for certain is that we cannot return to these places. We have already meddled too much in the affairs of others."
"It will be buried to be found when needed. Perhaps one day your children will make their way back, and I hope meet our children."
"But it is good to think our young will rise to another challenge, as brothers should, making trouble, finding strength."