Why do people say that the first 3 words of the preamble are most important?

We the people... are the the first three Words of the preamble to the constitution of the United States of America. People often consider and say that they are the most important three Words because the foundation of our land is fundamentally different than any other because it was formed and is expected to be run by ordinary people. Prior to its formation no country known to the founding fathers was run under anything except the divine right of kings which meant to the common man that the ruler ruled because God almighty had made him uniquely different from other humans and thus entitled to rule.