The authors of the Declaration of Independence were mostly influenced by John Locke and other English theorists, which were all part of what is called The British Liberalism. This political doctrine focused on protecting and enhancing individual freedom. They believed in the idea of social vontract in which government is a "necessary evil" to protect individuals from harm of others. The also recognised the government itself could be a threat to liberty, so their job was to make sure that doesn't happen. How? By devicing a system in which lwas, judges and police protect individual liberty.
The Declaration was also influenced by classical Republicanism based on ancient Greek and Rome(which prevented governmet power from getting out of control by vote) and christianity.