The main purpose of the Declaration of Independence was to state the fact that the colonies wanted to become independent from England. However, Jefferson wanted all people affected (both colonists and Englishmen) to understand why the colonists decided to declare independence.
In order to achieve this purpose, Jefferson employs various devices, one of which is pathos. Pathos refers to a rhetorical appeal based on emotions. In order to achieve this, Jefferson presents several arguments that are intended to give rise to an emotional response on the part of the readers. One example of this is the fact that Jefferson talks about the actions on the part of the king of England. He is considered to have been unresponsive and unsympathetic to the plight of the colonists. By presenting this argument, Jefferson hopes to convince the readers of the importance and legitimacy of independence.