In Introduction to Buddhism Geshe Kelsang gives us a brief overview of Buddha’s teachings:
Forty-nine days after Buddha attained enlightenment he was requested to teach. As a result of this request, Buddha rose from meditation and taught the first Wheel of Dharma.
These teachings which include the Sutra of the Four Noble Truths and other discourses, are the principal source of the Hinayana, or Lesser Vehicle, of Buddhism. Later, Buddha taught the second and third Wheels of Dharma, which include the Perfection of Wisdom Sutras and the Sutra Discriminating the Intention respectively. These teachings are the source of the Mahayana, or Great Vehicle, of Buddhism.
In the Hinayana teachings Buddha explains how to attain liberation from suffering for oneself alone, and in the Mahayana teaching he explains how to attain full enlightenment, or Buddhahood, for the sake of others. Both traditions flourished in Asia, at first in India and then gradually in other surrounding countries, including Tibet. Now they are also beginning to flourish in the West.
“Dharma” means “protection”. By practicing Buddha’s teachings we protect ourself from suffering and problems. All the problems we experience during daily life originate from ignorance, and the method for eliminating ignorance is to practice Dharma.
Practicing Dharma is the supreme method for improving the quality of our human life. The quality of life depends not upon external development or material progress, but upon the inner development of peace and happiness. For example, in the past many Buddhists lived in poor and underdeveloped countries, but they were able to find pure, lasting happiness by practicing what Buddha had taught.
If we integrate Buddha’s teachings into our daily life we will be able to solve all our inner problems and attain a truly peaceful mind. Without inner peace, outer peace is impossible.
If we first establish peace within our minds by training in spiritual paths, outer peace will come naturally; but if we do not, world peace will never be achieved, no matter how many people campaign for it.
Extensive presentations of Buddha’s teachings can also be found in Joyful Path, Ocean of Nectar, Heart of Wisdom, and Understanding the Mind.