I like to encourage as much actual roleplaying as possible within my group. To aid in that, I've written a few mission oaths that I will hopefully be able to get my fellow players to recite when we begin a mission.

I haven't finished all of them yet, but I thought I'd provide what I've got as a resource so you can use them as is or develop your own for your kill-team. There is certainly plenty of room for variation: an oath originating among the Space Wolves is likely to be very different from an oath handed down through the Blood Angels.

Please add your own oaths to this thread, and I will try to compile them in this first post. I reserve the right to correct spelling and grammatical errors.

Oath of Knowledge
(Leader) Knowledge is a shield.
(All) I shall gird myself against my enemy.
(Leader) Knowledge is a weapon.
(All) I shall bring death to my enemy.
(Leader) Knowledge is fear.
(All) I shall visit terror upon my enemy.
(Leader) Knowledge is victory.
(All) We will obliterate our enemy.

Oath of Loyalty
(Leader) Let no slight or false word come between us.
(All) For we are brothers.
(Leader) We stand united in the face of our enemies.
(All) For we are brothers.
(Leader) Our blood is the blood of the Emperor.
(All) For we are brothers.
(Leader) Our duty is the will of the Emperor.
(All) For we are brothers.
(Leader) We shall triumph in the name of the Emperor.
(All) For we are all brothers.

Oath of the Weapon
(Leader) Honour thy armoured harness.
(All) For it is the shield of the Emperor.
(Leader) Honour thy sacred bolt gun.
(All) For it is the sword of the Emperor.
(Leader) Spirits of the Machine, we beseech thee:
(All) In the name of the Emperor.
(Leader) Lend us thy fury and carry us to victory.
(All) For that is the will of the Emperor.

oooooh, nice

with your permission, i would from your work.

The rest of the Mission Oaths I came up with:

Oath of the Astartes
(Leader) We honour the deeds of our Fathers.
(All) Praise the Primarchs in the Emperor’s name.
(Leader) We hear the words of our Fathers.
(All) Their wisdom guides us to glory.
(Leader) We serve in the sight of our Fathers.
(All) Their eyes are upon us always.
(Leader) We fulfill the destiny of our Fathers.
(All) To the honour of the Primarchs, and the glory of the Emperor.

Oath to the Emperor
(Leader) By His wisdom we are given form.
(All) Hail the Master of Mankind.
(Leader) By His will we are given purpose.
(All) The word of the Emperor is the law of Man.
(Leader) By His sacrifice we are renewed.
(All) Praise the Golden Throne.
(Leader) In His name we shall triumph.
(All) Death to the enemies of the Emperor!

Oath of Glory
(Leader) By my blade, I shall be first into the fray.
(All) In the name of the sacred Primarch.
(Leader) By my armour, I shall not falter.
(All) For the honour of my Chapter.
(Leader) By my bolter, I shall slay all who stand against me.
(All) In the sight of my battle-brothers.
(Leader) On my honour, I shall achieve death or glory.
(All) In the name of the Emperor.

Really cool!!!

Super cool, these will get some use around my table. Excellent job.

Wow! These are, hands down, some of the best Space Marines chants I've ever read! You, my good man, are a credit to your Kill-team.

With your permission, Battle-Brother, I would like to use them on my future sessions of Deathwatch!

More, we need more!!!

I'll work on some Chapter-specific ones... Black Templars and Space Wolves lend themselves well to the subject. I get the impression from the core rules that the oath-taking may not involve the explicit invocation of a group oath, but it's fun for the group to all chime in (even if it feels a little corny at first).

Excellent work! I'll show these to my players. Will set the mood just right, I beleive.