The Vedas have been commented upon by different commentators, preached by great teachers, and sects founded upon them; and you find that in these books of the Vedas there are various apparently contradictory ideas. There are certain texts which are entirely dualistic, others are entirely monistic. The dualistic commentator, knowing no better, wishes to knock the monistic texts on the head. Preachers and priests want to explain them in the dualistic meaning. The monistic commentator serves the dualistic texts in a similar fashion.
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Now this is not the fault of the Vedas. It is foolish to attempt to prove that the whole of the Vedas is dualistic. It is equally foolish to attempt to prove that the whole of the Vedas is nondualistic. They are dualistic and non-dualistic both. We understand them better today in the light of newer ideas. These are but different conceptions leading to the final conclusion that both dualistic and monistic conceptions are necessary for the evolution of the mind, and therefore the Vedas preach them.
In mercy to the human race the Vedas show the various steps to the higher goal. Not that they are contradictory, vain words used by the Vedas to delude children; they are necessary not only for children, but for many a grown-up man. So long as we have a body and so long as we are deluded by the idea of our identity with the body, so long as we have five senses and see the external world, we must have a Personal God. For if we have all these ideas, we must take as the great Ramanuja has proved, all the ideas about God and nature and the individualized soul; when you take the one you have to take the whole triangle - we cannot avoid it. Therefore as long as you see the external world, attempting to avoid a Personal God and a personal soul is arrant lunacy.
But there may be times in the lives of sages when the human mind transcends as it were its own limitations, man goes even beyond nature, to the realm of which the Shruti declares,
There the eyes cannot reach nor speech nor mind
We cannot say that we know it, we cannot say that we do not know it.
There the human soul transcends all limitations, and then and then alone flashes into the human soul the conception of monism: I and the whole universe are one; I and Brahman are one. And this conclusion you will find has not only been reached through knowledge and philosophy, but parts of it through the power of love. You read in the Bhagavata, when Krishna disappeared and the Gopis bewailed his disappearance, that at last the thought of Krishna became so prominent in their minds that each one forgot her own body and thought she was Krishna, and began to decorate herself and to play as he did. We understand, therefore, that this identity comes even through love.
There was an ancient Persian Sufi poet, and one of his poems says,
I knocked at the door and from inside a voice came, 'Who is there?'
I replied, 'I am'. The door did not open.
A second time I came and knocked at the door and the same voice asked, 'Who is there?'
'I am so-and-so.' The door did not open.
A third time I came and the same voice asked, 'Who is there?'
'I am Thyself, my Love', and the door opened.