The Purpose of HR

I am working right now to put together a training on the subject of effective HR practices, and one of the first questions I plan on asking the training group is this:

"In one sentence, how would you describe the purpose of HR?"

In my research (a.k.a. Google search), here are some of the answers that I came across:

• HR's duty is to bring the best people into the best position.
• HR exists to protect a company from its employees.
• The purpose of HR is to fulfill organizational goals by implying tools which focuses on enhancing performance with concern for its employees.
• The purpose of human resources is to live.
• The HR department is to is there to guarantee that the right candidates get appointed to the right task at the right time and the job offered to them utilizes their capabilities to the maximum, adding to self-motivation and leading to better performance.
• HR is there to hire and fire.
• The HR function is to hire, train, motivate and support productive employees.
• An effective Human Resource department facilitates the execution of your company’s mission within the boundaries of employment law.
• HR's sole purpose is to take the fun out of work for everyone.

I have my own thoughts on the issue, which I will save those for another post. But I want to hear your perspective. Do any of the answers listed above ring true to you? Or is there a better way that you would describe HR's purpose?