This is what should be done by one who is skilled in goodness
And who knows the path of peace:
Let them be able and upright, straightforward and gentle in speech,
Humble and not conceited, contented and easily satisfied.
Unburdened with duties and frugal in their ways.
Peaceful and calm, and wise and skilful,
not proud and demanding in nature.

Let them not do the slightest thing that the wise would later reprove.
They should wish:

In gladness and in safety
May all beings be at ease.
Whatever living beings there may be,
Whether they are weak or strong, omitting none,
The great or the mighty, medium, short or small,
The seen and the unseen,
Those living near and far away,
Those born and to-be-born,
May all beings be at ease!

Let none deceive another, or despise any being in any state,
Let none through anger or ill-will wish harm upon another.

Even as a mother protects with her life her child, her only child,
So with a boundless heart should one cherish all living beings,
Radiating kindness over the entire world,
Spreading upwards to the skies, and downwards to the depths,
Outwards and unbounded, freed from hatred and ill-will.

Whether standing or walking, seated or lying down,
Free from drowsiness, one should sustain this recollection.

- Metta Sutta, from Pali Canon