A Calm and Peaceful Mind
The mind is purified by cultivating thoughts and feelings of friendship for others, compassion for those who are suffering, happiness for the well-being that others enjoy, and dispassion regarding bad behavior.
~The Yoga Sutras of Patanjali 1:33
The Yoga Sutras of Patanjali is an ancient text that give us guidance on meditation and ethical living. The word sutra comes from the same root as the word thread.
A calm and peaceful mind is cultivated by how we interact in the world, going hand in hand with our meditation practice. When encountering people who are happy, be friendly and supportive. To those who are suffering, cultivate compassion, rather than being annoyed or afraid. Be happy for those who have fortunate circumstances rather than being jealous of them. Disregard disturbing circumstances, rather than becoming upset by them. Do what you can to respond appropriately, but don't let the circumstance disturb your peace.