Only recently was I introduced to the Metta chant. The practice of chanting these words reinforces our aspiration to feel true compassion for all beings — and very specifically, not only the nice ones, but also including the most horrible, awful people we can imagine.
The chant starts with us, ourselves:
Aham avero homi
May I be free from enmity and danger
May I be free from mental suffering
May I be free from physical suffering
Then it continues:
May all beings
all breathing things
sabbe bhutta …
all creatures …
be free from enmity and dangers
be free from mental suffering
be free from physical suffering
sukhi – attanam pariharantu
may they take care of themselves happily
May all being be free from suffering
Yattha-laddha-sampattito mavigacchantu …
May whatever they have gained not be lost …
You can read the complete chant here, at BuddhaNet.
The Metta Sutra is a different text (read a good English translation here). The teaching is the same:
As a mother would risk her life
to protect her child, her only child,
even so should one cultivate a limitless heart
with regard to all beings.
With good will for the entire cosmos,
cultivate a limitless heart:
Above, below, and all around,
unobstructed, without enmity or hate.