The symbol of the Space Marines.  This special knife is only carried by Space Marines.  And is given only after completion of Space Marine School.  In special instances, and based on valor, Space Marine field commanders are authorized to deputize Starfleet personnel as Space Marines and bestow upon them The Knife.

It is both, supremely utilitarian and tremendously deadly.  Special features include a secondary, spring-fired, dagger contained within the main blade and a force generator.
 
 
 

 "This is My Knife."
"There are not many like it, bit this one is mine."
"My knife is my best friend. It is my life"
"I must master it as I master my life."
"My knife, without me is useless."
"Without my knife, I am useless."
"I must direct  my knife true."
"I must cut straighter than my enemy, who is trying to defeat me."
"I must cut him before he cuts me down."
"I know that what counts is not the battle."
"I know that it is the hits that counts."
"My knife is human, even as I, because it is my life."
"Thus, I will learn it as a companion."
"I will learn its weakness and its strength."
"I will keep my knife clean and ready, even as I am clean and ready."
"We will become part of each other."
"My knife and I are the defenders of my galaxy."
"We are the masters of our enemy."
"We are the saviors of my life."
"My Life---My Knife"
"So be it, unit victory is ours, and there is no enemy, Only Peace."