that they [all men] are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.

The phrase you're referencing is from the United States Declaration of Independence, written in 1776. It asserts that all men are inherently granted certain rights by their creator, including the rights to life, liberty, and the pursuit of happiness. This statement forms the foundational principles of human rights and individual freedoms in many democratic societies.