The way to be happy is to live according to Nature, in obedience to that universal and unalterable law with which every heart is originally impressed; which is not written on it by precept, but engraven by destiny; not instilled by education, but infused at our nativity.
 Samuel Johnson, The History of Rasselas, Prince of Abissinia (1759). copy citation

Context

““ This, ” said a philosopher who had heard him with tokens of great impatience, “ is the present condition of a wise man. The time is already come when none are wretched but by their own fault. Nothing is more idle than to inquire after happiness which Nature has kindly placed within our reach. The way to be happy is to live according to Nature, in obedience to that universal and unalterable law with which every heart is originally impressed; which is not written on it by precept, but engraven by destiny; not instilled by education, but infused at our nativity. He that lives according to Nature will suffer nothing from the delusions of hope or importunities of desire; he will receive and reject with equability of temper; and act or suffer as the reason of things shall alternately prescribe.” source