The Path of Concentration & Mindfulness
Every time he explains mindfulness and its place in the path, he makes it clear that the purpose of mindfulness practice is to lead the mind into a state of Right Concentration — to get the mind to settle down and to find a place where it can really feel stable, at home, where it can look at things steadily and see them for what they are.
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To be in jhana is to be absorbed, very pleasurably, in the sense of the whole body altogether. A very broad sense of awareness fills the entire body. One of the images the Buddha used to describe this state is that of a person kneading water into dough so that the water permeates throughout the flour. Another is a lake in which a cool spring comes welling up and suffuses the entire lake.
http://www.accesstoinsight.org/lib/authors/thanissaro/concmind.html