Suffering originates from various causes and conditions. But the root cause of our pain and suffering lies in our own ignorant and undisciplined state of mind. The happiness we seek can be attained only through the purification of our minds.
If you cannot stop worrying over something in the past or what might happen in the future, shift your focus to the inhalation and exhalation of your breath. Or recite this mantra: om mani padme hum (pronounced "om mani padmay hum"). Since the mind cannot concentrate on two things simultaneously, either of these meditations causes the former worry to fade---How to Practice: The Way to a Meaningful Life
