Four noble truths & the noble eightfold path [Buddhist teaching]

FOUR NOBLE TRUTHS:


 
    This Dhamma, or universal moral law discovered by the Buddha, is
  summed up in the Four Noble Truths: the truths about the universal
  sway of suffering, about its origin, its extinction, and the path
  leading to its extinction.
 
    (I) The First Truth, about the universality of //suffering//,
  teaches, in short, that all forms of existence are of necessity
  subject to suffering.
 
    (II) The Second Truth, about the //origin of suffering//, teaches
  that all suffering is rooted in selfish //craving// and //ignorance//,
  in //tanha// and //avijja//. It further explains the cause of this
  seeming injustice in nature, by teaching that nothing in the world can
  come into existence without reason or cause; and that not only all our
  latent tendencies, but our whole destiny, all weal and woe, results
  from causes which we have to seek partly in this life, partly in
  former states of existence.
 
    The second truth further teaches us that the future life, with all
  its weal and woe, must result from the seeds sown in this and former
  lives.
 
    (III) The Third Truth, or the truth about the //extinction of
  suffering//, shows how, through the extinction of craving and
  ignorance, all suffering will vanish and liberation from this Samsara
  be attained.
 
    (IV) The Fourth Truth shows the way, or the means by which this
  goal is reached. It is the Noble Eightfold Path of right
  understanding, right thought, right speech, right bodily action, right
  livelihood, right effort, right mindfulness and right concentration of
  mind.
 
    From these Four Noble Truths we shall pick out and clear up such
  points as are essential for a general knowledge of the Dhamma. In
  doing so, we shall at the same time refute a number of widespread
  prejudices concerning the Buddha's teaching.

EIGHTFOLD NOBLE PATH:
 
    Let us, however, first outline the Noble Eightfold Path, for it is
  this path of righteousness and wisdom that really constitutes the
  //essence of Buddhist practice// -- the mode of living and thinking to
  be followed by any true follower of the Buddha.
 
    (1) The first stage of the Eightfold Path is, as already stated,
  Right Understanding, i.e. understanding the true nature of
  existence, and the moral laws governing the same. In other words, it
  is the right understanding of the Dhamma, i.e. of the Four Noble
  Truths.
 
    (2) The second stage of the Eightfold Path is Right Thought,
  i.e. a pure state of mind, free from sensual lust, from ill-will, and
  from cruelty; in other words, thoughts of self-renunciation, of
  goodness, and of mercy.
 
    (3) The third stage is Right Speech. It consists of words which
  are not false, not harsh, not scandalous, not frivolous, i.e. truthful
  words, mild words, pacifying words, and wise words.
 
    (4) The fourth stage is Right Bodily Action, i.e. abstaining
  from intentional killing or harming of any living creature, abstaining
  from dishonest taking of others' property, abstaining from adultery.
 
    (5) The fifth stage is Right Livelihood, i.e. such a livelihood
  as does not bring harm and suffering to other beings.
 
    (6) The sixth stage is Right Effort. It is the fourfold effort
  which we make in //overcoming// old and //avoiding// fresh bad actions
  by body, speech and mind; and the effort which we make in
  //developing// fresh actions of righteousness, inner peace and wisdom,
  and in //cultivating// them to perfection.
 
    (7) The seventh stage is Right Mindfulness, or alertness of
  mind. It is the ever-ready mental clarity whatever we are doing,
  speaking, or thinking and in keeping before our mind the realities of
  existence, i.e. the impermanence, unsatisfactoriness and phenomenality
  (//anicca//, //dukkha//, //anatta//) of all forms of existence.
 
    (8) The eighth stage is Right Concentration of mind. Such a
  kind of mental concentration is meant, as is directed towards a
  morally wholesome object, and always bound up with right thought,
  right effort and right mindfulness.
 
    Thus the Eightfold Path is a path of morality (Sila), of mental
  training (Samadhi), and of wisdom (Panna).
 
    //Morality// therein is indicated by right speech, right bodily
  action, and right livelihood. //Mental training// is indicated by
  right effort, right mindfulness, and right concentration of mind. And
  //wisdom// is indicated by right understanding and right thought.
 
    Thus this liberating Eightfold Path is a path of inner culture, of
  inner progress. By merely external worship, mere ceremonies and
  selfish prayers, one can never make any real progress in righteousness
  and insight. The Buddha says: "Be your own isle of refuge, be your own
  shelter, seek not for any other protection! Let the truth be your isle
  of refuge, let the truth be your shelter, seek not after any other
  protection!" To be of real effect, to ensure an absolute inner
  progress, all our efforts must be based upon our own understanding and
  insight. All absolute inward progress is rooted in right
  understanding, and without right understanding there is no attainment
  of perfection and of the unshakable peace of Nibbana.
 
    Belief in the moral efficacy of mere external rite and ritual
  (//silabbata-paramasa//) constitutes, according to the Buddha's
  teaching, //a mighty obstacle to inner progress//. One who takes
  refuge in mere external practices is on the wrong path. For, in order
  to gain real inner progress, all our efforts must necessarily be based
  on our own understanding and insight. Any real progress is rooted in
  right understanding, and without right understanding there will be no
  attainment of unshakable peace and holiness. Moreover, this blind
  belief in mere external practices is the cause of much misery and
  wretchedness in the world. It leads to mental stagnation, to
  fanaticism and intolerance, to self-exaltation and contempt for
  others, to contention, discord, war, strife and bloodshed, as the
  history of the Middle Ages quite sufficiently testifies. This belief
  in mere externals dulls and deadens one's power of thought, stifles
  every higher emotion in man. It makes him a mental slave, and favours
  the growth of all kinds of hypocrisy.

Source : http://www.angelfire.com/indie/anna_jones1/fundamental.html#N10