After Shay's Rebellion, the people were frightened. The Constitution insured peace among the people and no random wars would brake out.
The Article of Confederation insured militia to protect the town, but the Constitution allows the government to take care of and support a military to protect our country.
The Declaration of Independence promoted the idea of life, liberty and the "pursuit of happiness." The Constitution promotes the idea of the well-being of people in general. The Constitution does this by maintaining order, protecting individual rights, regulating commerce and bankruptcies, and promoting science and technology by granting patents.