The Marine NCO, the Marine Non-Commissioned Officer.  Tales of their combat exploits have become the stuff of legend.  NCOs are the Corporals and Sergeants responsible for the lives of their men in combat.  They must be leaders of men, but also much more.  They carry with them the unbroken traditions of duty and dedication to their assigned mission.  Their creed need not be lengthy.  It is short, succinct, and to the point:

NCO Creed:

I am an NCO dedicated to training new Marines and influencing the old.  I am forever conscious of each Marine under my charge, and by example will inspire him to the highest standards possible.  I will strive to be patient, understanding, just, and firm.  I will commend the deserving and encourage the wayward.

I will never forget that I am responsible to my Commanding Officer for the morale, discipline, and efficiency of my men.  Their performance will reflect an image of me.

What was the original NCO Creed?

I am the backbone of the United States Marine Corps, I am a Marine Non-Commissioned Officer. I serve as part of the vital link between my commander (and all officers) and enlisted Marines. I will never forget who I am or what I represent. I will challenge myself to the limit and be ever attentive to duty.

I am now, more than ever, committed to excellence in all that I do, so that I can set the proper example for other Marines. I will demand of myself all the energy, knowledge and skills I possess, so that I can instill confidence in those I teach. I will constantly strive to perfect my own skills and to become a good leader. Above all I will be truthful in all I say or do. My integrity shall be impeccable as my appearance. I will be honest with myself, with those under my charge and with my superiors.

I pledge to do my best to incorporate all the leadership traits into my character. For such is the heritage I have received from that long, illustrious line of professionals who have worn the bloodstripe so proudly before me. I must give the very best I have for my Marines, my Corps and my Country for though today I instruct and supervise in peace, tomorrow, I may lead in war.

This should answer the questions:
What is the NCO Creed?
What was the original NCO Creed?