Hark ye, who are pure in the eyes of the Emperor. Hark now, as I, your loyal Orator, recite this, the Apocryphon Oath, of one of His most holy Space Marines.

Let it be known by all dominions, powers and authorities, that the bearer of this seal, Brother <name> of the <Chapter>, has taken the most sacred Apocryphon Oath, and has been seconded to the Deathwatch until such time of his death, or until the specifics of his oath shall be considered and proclaimed to be discharged.

On the honor of your chapter, your Primarch, and the Emperor, you are sworn to destroy the Alien, confront the myriad enemies of the imperium, and obey the most solemn vows of the Apocryphon Conclave. You will watch in the dark places, you will safeguard the night, and annihilate the vile xenos and bring unto them the judgment of mankind. You will stand as the bulwark upon which the Imperium persists, from now, unto the ending of the universe. 

The bearer of this oath will be accorded the utmost honor in word and deed.  Let all know that the gaze of the Emperor and the blessed Primarchs shall follow the bearer wherever he deigns to tread, so that even in death, they shall know his name.

So it is sealed, by word, blood and deed, by the grace of the Apocryphon Conclave, the Deathwatch, and the Senatorum Imperialis. 

To be Unclean that is the Mark of the Xenos

To be Impure that is the Mark of the Xenos

To be Abhorred That is the Mark of the Xenos

To be Reviled That is the Mark of the Xenos

To be Hunted That is the Mark of the Xenos

To be Purged That is the fate of the Xenos

To be Cleansed For that is the fate of all Xenos

We bring justice by sword, by shell, by flame. In his name, suffer not the alien to live!

And to be seen and not heard is as easy as pushing the Publish button.

Oath on brother!  Oath on oh never mind just shoot something when your done with that.