All sentient beings is a lot of people (and not just people — “sentient beings” includes all life forms capable of experiencing pain or pleasure). How do we develop feelings of Metta for all beings?
In the fifth stage we’re working on developing Metta as an open attitude of loving. It’s as if we are a blazing sun of positive emotion that warms all beings. We’re working towards being so radiant that whoever comes into our experience will be received with metta — with friendliness, warmth, and caring. This may sound like a tall order, but think back to those days when, for some reason, you’ve been in an unshakably good mood and nothing could annoy you. That’s the kind of state we’re trying to encourage, only we want to be like that all the time, not just on those days.
The four directions
Buddhist monks were traditionally encouraged to walk around radiating metta in the four directions of space. In the fifth stage you can just imagine that you are sending Metta out in all directions, or thinking about each geographical direction and wishing that all beings in that direction be well and happy.
Holding the world in your heart
You can imagine that you hold the world enfolded in your heart, and cherish it.
Taking a world tour
You can let scenes from around the world come into your mind, and the people you see there you can wish well.
You don’t have to be limited to places you know — you must have seen a lot of the world on television, in magazines, and in the movies.
You can call to mind people around the world who you know. You can imagine your Metta flowing to them, and through them to all the people that they know, and so on…
You can remember to include animals, too!
And there’s no need to stop with planet earth. You can send your metta throughout the universe, to any sentient beings that might be out there.