Very often I hear aspirants say that they cannot concentrate for more than five minutes. After five minutes they get a headache or feel that their head is on fire.
Why? It is because the power of their concentration is coming from the intellectual mind or, you can say, the disciplined mind. The mind knows that it must not wander; that much knowledge the mind has. But if the mind is to be utilised properly, in an illumined way, then the light of the soul has to come into it. When the light of the soul has entered into the mind, it is extremely easy to concentrate on something for hours. During this time there will be no thoughts or doubts or fears. No negative forces can enter into the mind if it is surcharged with the soul's light.
When we concentrate we have to feel that our power of concentration is coming from the heart centre and then going up to the third eye. The heart centre is where the soul is located. When we think of the soul at this time, it is better not to form any specific idea of it or try to think of what it looks like. Only we will think of it as God's representative or as boundless light and delight.
When we concentrate, we try to feel that the soul's light is coming from the heart and passing through the third eye. Then, with this light, we enter into the object of concentration and identify with it. The final stage of concentration is to discover the hidden, ultimate Truth in the object of concentration.