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we are all familiar with the phrase 'light spilled out' but not 'darkness spilled out'. this implies that light moves into areas where there is no light and drives away darkness, so to speak.
darkness can never drive away light. darkness cannot survive where there is light.
the same is also applicable to knowledge.
- knowledge drives away ignorance.
- ignorance cannot survive with knowledge.
- knowledge spreads ... not ignorance. (though rumors tend to spread like wild-fire :-) i believe rumors are a version of the truth!)
- we are never comfortable with ignorance (though we do say ignorance is bliss!)... knowledge never feels like a burden.
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and now when you apply this to happiness,
- whenever the cause of sorrow is removed we become happy... it shines forth from within us.
- sorrow departs from within us and what remains is happiness.
- sorrow can be spread but you don't find any eager buyers for it. happiness can be spread and nobody turns it away.
- and happiness is never a burden... unlike sorrow.
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according to vedanta, knowledge and happiness are aspects of our true nature. and anything which is our true nature will always come naturally to us. we will never shun it... it is never a burden.