What is the reason of Preamble of the constitution?

Question

What is the reason

Answer 1

To explain why the dissenters are forming a new nation, what they want to escape from and what they want to achieve.

Answer 2

It was what the founding fathers thought the Constitution meant and what they hoped to achieve.

Answer 3

A preamble explains the purpose of a document.  In one paragraph the peamble of the U.S Constitution not only explains the purpose of the constitution, but sums up the wisdom of millennia.  It provides a road map towards the future by prscribing justice, tranquility, heart, and equlity as organic intentions of the rule of law.