When you think about how we define Compassion and Lovingkindness, Compassion is wishing that there are no problems; Lovingkindness is a wishing for happiness on top of that. Because, quite frankly, when we think of a problem in this planet - for example, a lot of people starving to death - we wish they did not starve, we wish everyone had enough food so that they wouldn't starve. That's a wonderful wish, that in itself is the Compassionate wish, and that's a wonderful wish; but it doesn't necessarily mean that everyone will automatically have happiness. So the Lovingkindness is a little extra bit we put on top of the Compassion, where we actually want them to be happy as well, not just relieved of starving, but actually to have the opportunity to be happy as well. So this is a differentiation between the two, and some teachers don't do this, they don't define it the same way as us, but this is how we look at them. Compassion is the wish there wasn't a problem; Lovingkindness is the wishing that happiness is there instead of the problem.
Now, as to how it's expressed, to a large extent I'm not sure there's a big difference between how the two are expressed because, really, we'd like to express them together. Say you see some kid fall off their bicycle. They scratch up their knee, they're crying and they're only ten years old, what do you do? Do you cry with them? Do you laugh at them? Most good adults will go and help the little kid. Without hardly thinking, without even kind of defining what's going on in their brain, they have a Compassionate wish to help the kid end their suffering and most adults will try to make the kid happy at the same time - out comes a candy bar or anything to get the kid to be happy as well. So really, they are so closely connected, we're not going to separate them and have a different way of expressing each one; we're going to express them together.
Also, they balance well together. If you go throughout your life only having a Compassionate wish for everyone, what it means is that you are looking at the suffering and problems in the world, over and over, and you're wishing it wasn't there, over and over, and you're wishing it wasn't there, over and over, and you're wishing it wasn't there and, yeah, you can get pretty wiped out. The Lovingkindness tells us that there is a way out and there's a way to find happiness. And, right here in our meditation practice, we're learning some methods, techniques and tools, that can help us to be more happy, okay.
Coming back to the kid that falls off the bike, we know ways to make the kid happy. So, in a sense, we do want them together in order to balance, because if we only focus on problems in the world and we have lots of Compassion, lots of Compassion, lots of Compassion, it gets heavy, really heavy. So we want to have that Lovingkindness side that says, "Oh yeah, there are problems but there's also a way out, there's also a way out."