"And the Buddha highly recommends the attitudes we were chanting just now unlimited goodwill, unlimited compassion, unlimited empathetic joy or appreciation and unlimited equanimity. In other words, put yourself in a position where you can feel these emotions for anybody.
Basically you start out with goodwill. Reminding yourself there's no need to see anybody in the world suffer, because if people are suffering that's why they tend to do evil things. They feel threatened, they feel attacked, they feel like they are in a weak position and so they strike out. So no matter how much you may dislike a particular person, there is really no reason to wish ill on them. What you do is wish for this person to find true happiness. If they could find true happiness within, the disagreeable behavior that they're engaging in would fall away. At the same time, if you can develop goodwill for everybody, it's a lot harder to harm people, harm yourself or harm anyone else. It strengthens your resolve not to repeat your mistake.
The same with compassion that's to be directed to people you see are suffering. You don't want to pile more suffering on top of them. You find yourself in a position where you can help, ok, you go ahead, you're happy to help. And even if you're not, you extend that wish may they be relieved from their suffering, so that maybe someday you do find yourself in a position where you can help and you can carry through.
As for empathetic joy, that's when you see people are happy and you remind yourself not to be jealous of their happiness. You don't resent their happiness. Try to put yourself in their place. As the Buddha once said, if you see somebody really miserable and suffering, remind yourself you've been there. You see a leper on the side of the road, sticking a burning stick into his wounds because they hurt so much, trying to numb the sensation of the itch. He says you've been there. When someone's really wealthy, look at them and you realize, you've been there too. It should give you a sense of dismay over the ups and downs of this wandering on. But what it also means is that when you see somebody suffering, remind yourself you're not a better person than they are necessarily. And you're not immune to that suffering in the future. So you do what you can to help.
When someone's happy, remind yourself you've been there too. You realize that whatever the happiness may be, it tends to pass. And it's not a relative measure of how much good karma you have in the past as opposed to theirs if they are happier than you, or wealthier than you or whatever. There's no such thing as a single karma account with a running balance. We have lots of different actions in the past and different actions have seeds that will sprout at different times. Sometimes some of them take a long time, some of them take a short time. So there is no need to be jealous of anyone else's happiness.
Finally equanimity is when there are situations where you really can't help. Someone is really suffering, and there is really nothing you can do for them. You develop equanimity. It's not a hardhearted equanimity. It's just you realize you can't let your happiness rise and fall with theirs, because you've got other things you need to do, other areas where you can be of help. You want to focus on those.
The trick here is learning how to develop these emotions when you need them. All too often our attitude towards our emotions is that they're a given. You hear the Buddha saying you can actually change your emotions. This is an important skill, that you can feel goodwill for anyone at any time when it's called for. You can feel compassion, empathetic joy, any time for anyone when it's called for. You can develop equanimity even in cases where people are close to you, you want very much to help them, but you can't. You've got to develop equanimity. And this requires skill."
From: Living Forwards, Understanding Backwards by Thanissaro Bhikkhu
For Free Distribution, as a gift of Dhamma, from Access to Insight and Thanissaro Bhikkhu
With metta / Antony.