Mentally repeat, “Let all beings be happy; let all beings be peaceful; let all beings be blissful.” So do to the east, south, north and west. The more you do that the better you will feel yourself. You will find at last that the easiest way to make ourselves healthy is to see that others are healthy, and the easiest way to make ourselves happy is to see that others are happy. After doing that, those who believe in God should pray — not for money, not for health, nor for heaven; pray for knowledge and light; every other prayer is selfish. Then the next thing to do is to think of your own body, and see that it is strong and healthy; it is the best instrument you have. Think of it as being as strong as adamant, and that with the help of this body you will cross the ocean of life. Freedom is never to be reached by the weak. Throw away all weakness. Tell your body that it is strong, tell your mind that it is strong, and have unbounded faith and hope in yourself.
– Raja-Yoga & Patanjali Yoga-Sutra by Swami Vivekananda