Some Teachings of Ramana Maharishi
It is with the inward-going mind that you eliminate the outward-going mind.
You do not set about saying there is a mind and I'm going to kill it, but you seek the source of the mind. Then you will find that the mind does not exist at all.
The mind, turned outwards, results in thoughts and objects. Turned inwards, it becomes itself the Self.
To ask the mind to kill the mind is like making the thief the policeman. He will go with you and pretend to catch the thief, but nothing will be gained.
So you must turn inward and see from where the mind rises and then it will cease to exist.
Whenever you are disturbed by thoughts you need merely withdraw within to the Self. This is not concentration or destruction of the mind but withdrawal into the Self.
The degree of the absence of thoughts is the measure of your progress towards Self-realization. But Self-realization itself does not admit of progress, it is ever the same.
The Self remains always in realization. The obstacles are thoughts.
Progress is measured by the degree of removal of the obstacles to understanding that the Self is always realized. So thoughts must be checked by seeking to whom they arise. Go to their source and they will not arise.