When someone practices playing the clarinet, they do that to become
better at playing the clarinet. They become able to play pleasant
sounds and melodies. When someone practices shamatha meditation
(concentration meditation), they do that to become better able to focus
the mind on something-- and maintain this focus.
This material world, this samsara, which we live in and are interacting
with most all of the time is a changing world. Change is simply a
property of all matter. Due to emotional and cognitive obscurations
(nyon-sgrib and shes-sgrib), what of the world and how the mind (sem)
experiences the world changes also. To achieve enlightenment, all
obscurations must vanish to unveil rigpa. How, then, does meditation
help us do that?