What document does lincoln refer with the words "all men are created equal"?

The Declaration Of Independence, is what Lincoln was referring to in this case :)  

The second paragraph of the Declaration of Independence states, "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."

Not sure this is a hard one huh