If you exclude the Preamble, the Declaration of Independence can be divided into three parts. The first part declares the rights of citizens and is heavily influenced by the works of the English political philosopher John Locke. This is the portion that has the famous line about "unalienable rights."
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of happiness.
The first part also asserts that if a government fails to protect these rights, the citizens have the duty to remove that government. This transitions nicely into the second part of the Declaration of Independence which outlines how the King and Parliament have not protected the rights of the colonists. Twenty-seven grievances in all are listed. An example of a grievance from the document:
He has refused for a long time, after such dissolutions, to cause others to be elected; whereby the Legislative powers, incapable of Annihilation, have returned to the People at large for their exercise; the State remaining in the mean time exposed to all the dangers of invasion from without, and convulsions within.
The third part of the document is the official declaration that grants the colonists freedom and independence from England. This portion is the major purpose of the document in the first place and the reason Independence Day is celebrated on the day the document was signed.
....solemnly publish and declare, That these United Colonies are, and of Right ought to be Free and Independent States; that they are Absolved from all Allegiance to the British Crown, and that all political connection between them and the State of Great Britain, is and ought to be totally dissolved.....
The Declaration of Independence has several parts. The first part stated that when a group of people wants to be free from another group of people, the people should explain why they want to be free. This section is called the preamble.
The second part of the Declaration of Independence explained that people have rights that can’t be taken away. These rights include the right to life, liberty, and the pursuit of happiness. They are known as unalienable rights. Additionally, the job of government is to protect our rights. When government fails to protect our rights, the people must remove that government.
The third section of the Declaration of Independence, which is the largest section, is the list of complaints against the King. The colonists had many complaints about the actions of the King as well as the British government. The statement that said we were now free from British rule followed the third section.