The Buddha taught metta (loving-kindness) as one of the four divine abodes, a practice for cultivating boundless love toward all living beings.
How to Practice
Sit quietly and begin by directing loving wishes toward yourself: 'May I be happy. May I be at peace.'
Self-compassion is the foundation -- you can't give what you don't have.
Bring to mind someone you love and send them the same wishes: 'May you be happy. May you be safe.'
Starting with someone easy warms the heart naturally.
Extend the wishes to a neutral person -- someone you neither like nor dislike.
This stretches your compassion beyond your comfort zone.
If ready, include a difficult person: 'May you be free from suffering.'
This is the hardest step but the most transformative one.
Finally, send loving-kindness to all beings everywhere: 'May all beings be happy and free.'
Universal kindness is the ultimate expression of metta.