There are many wonderful translations of the metta sutta. I’m not saying this is better than any of the others, but I wanted to try my hand at it, and give it the simple|suttas treatment.
To train in goodness, to find peace
This is what has to be done:
Be capable and honest,
Modestly accept criticism,
Be content with little,
Take on few responsibilities,
Be frugal, calm, and humble,
Put aside all greed for worldly things,
Avoid even the smallest action, that could be criticized by the wise.
Make a heartfelt wish: “May every living creature be happy and safe,
Their hearts full of joy,
Every being that breaths, whatever size or shape.
Seen and unseen, near and far,
Born and about to be born,
May they all be filled with happiness.”
Do not deceive or despise anyone whatsoever,
Nor allow anger or hatred to cause you to wish them harm,
Just as a mother would defend her only child, even with her own life,
In just this way, you should cultivate boundless love for all beings.
Radiating kindness throughout the whole world,
Above and below and throughout,
Free from hate, free from the slightest cruelty.
Be energetically mindful of this practice at all times:
While standing, walking, or lying down.
For this is the highest, most sublime state.
If you avoid unwise views, greed,
and desire for the pleasures of the senses,
And hold fast to your virtue and insight,
You will never be born again into this world.
-Karaniya Metta Sutta (Sutta Nipāta 1.8)