The Buddha's first sermon after his Enlightenment centered on the  Four Noble Truths, which are the foundation of Buddhism.
                                    The truths are:  
  - The truth of suffering (dukkha) 
 - The truth of the cause of suffering (samudaya)
                                    
 - The truth of the end of suffering (nirhodha) 
 - The truth of the path that frees us from suffering
                                    (magga)
 
  Let's look at one truth at a time. 
  The Truth of Suffering
   The First
                                    Noble Truth often is translated as "Life is suffering."  Many people new to Buddhism tune out as soon as they hear
                                    this. But the  Pali word dukkha also refers to anything that is temporary,  conditional, or compounded of other things.
                                    Even something precious and  enjoyable is dukkha, because it will end. 
    Related to the nature of life is the nature
                                    of self. Are we not also  temporary, conditional and compounded of many parts? We can understand  that life is impermanent
                                    but are we, also, impermanent? The Buddha  taught that before we can understand life and death we must understand  the self.
                                    
     Read More: What is the self? 
 Read More: What the Buddha Meant by "Suffering"
  The Truth of the Cause of Suffering
   The Second Noble Truth teaches that the cause of suffering is craving
                                    or thirst (tanha).  We continually search for something outside ourselves to make us happy.  But no matter how successful
                                    we are, we never remain satisfied. 
  The Buddha taught that this thirst grows from ignorance of the self.  We go through
                                    life grabbing one thing after another to get a sense of  security about ourselves. We attach not only to physical things,
                                    but  also to ideas and opinions about ourselves and the world around us. Then  we grow frustrated when the world doesn't
                                    behave the way we think it  should and our lives don't conform to our expectations. 
    The Buddha's teachings
                                    on karma and rebirth are closely related to the Second Noble Truth. 
  Read More: Karma and Rebirth
  The Truth of the End of Suffering
   The Buddha's teachings on the Four Noble Truths are sometimes  compared
                                    to a physician diagnosing an illness and prescribing a  treatment. The first truth tells us what the illness is, and the second
                                     truth tells us what causes the illness. The Third Noble Truth holds out  hope for a cure. 
  The Buddha taught that
                                    through diligent practice, we can put an end  to craving. Ending the hamster-wheel chase after satisfaction is  enlightenment
                                    (bodhi, "awakened"). The enlightened being exists in a state called Nirvana. 
  Read
                                    More: Enlightenment and Nirvana
  The Truth of the Path That Frees Us From Suffering
   Here the Buddha as physician prescribes the treatment
                                    for our  illness: The Eightfold Path. Unlike in many other religions, in Buddhism  there is no particular benefit to merely
                                    believing in a doctrine.  Instead, the emphasis is on living the doctrine and walking the path.