The full transcription of the relevant scene from Full Metal Jacket. It is based on the true creed of a Marine in the United States Marine Corps:
 

Gunnery Sergeant Hartman: Tonight, you pukes will sleep with your rifles.  You will give your rifle a girl's name because this is the only pussy you people are going to get.  Your days of finger-banging ol' Mary Jane Rottencrotch through her pretty pink panties are over!

...PRAY.
 

MarinesThis is my rifle. There are many like it, but this one is mine. My rifle is my best friend. It is my life. I must master it as I must master my life. Without me, my rifle is useless. Without my rifle I am useless. I must fire my rifle true. I must shoot straighter than my enemy, who is trying to kill me. I must shoot him before he shoots me. I will. Before God I swear this creed: my rifle and myself are defenders of my country, we are the masters of my enemy, we are the saviors of my life.  So be it, until there is no enemy, but peace. Amen.