they think about business instead of sleep and wonder why they
don't sleep. This is the wrong kind of concentration and is
dangerous. It is involuntary. When you are unable to get anything
out of your mind it becomes unwholesome as any thought held
continuously causes weariness of the flesh. It is a big mistake
to let a thought rule you, instead of ruling it. He who does not
rule himself is not a success. If you cannot control your
concentration, your health will suffer.

So never become so absorbed with anything that you cannot lay it
aside and take up another. This is self-control.

Concentration Is Paying Attention to a Chosen Thought. Everything
that passes before the eye makes an impression on the
subconscious mind, but unless you pay attention to some certain
thing you will not remember what you saw. For instance if you
walked down a busy street without seeing anything that attracted
your particular attention, you could not recall anything you saw.
So you see only what attracts your attention. If you work you
only see and remember what you think about. When you concentrate
on something it absorbs your whole thought.

Self-Study Valuable. Everyone has some habits that can be
overcome by concentration. We will say for instance, you are in
the habit of complaining, or finding fault with yourself or
others; or, imagining that you do not possess the ability of
others; or feeling that you are not as good as someone else; or
that you cannot rely on yourself; or harboring any similar
thoughts or thoughts of weakness. These should be cast aside and
instead thoughts of strength should be put in their place. Just