Thanissaro Bhikkhu "The Body In & Of Itself", 9min mp3 audio,

And after a while you notice that the mind, if it has a chance to settle down and be still, has a sense of well-being.

The Buddha once said there is no happiness other than peace, N’atthi santi param sukham. You might argue you can think of all kinds of happiness that are not very peaceful at all. But are they really happiness? There's a sense of excitement, there's a sense of thrill – but there's an awful lot of stress that goes in with those feelings and you can't endure them very long. The sense of ease, however, that comes with this peace: this you can endure for long periods at a time. The mind gets grounded, has a sense of solidity, stability. It doesn't have to jump around the way it used to." ~