Sastras Stress Purity of Speech
Sastras teach man many subtle matters. Subtle here means matters not within his analytical acumen to grasp. They may, in fact, appear even ordinary to some people. However, there is the possibility that man overlooks some matters in his haste.
For example, when a man gets angry or when something unpleasant happens, he will invariably blame others. He might also lash out a stream of coarse invective. Only later, when he cools down, he will realise that he should have controlled his outburst and should have been more temperate in his language.
But, even before that, the person at the receiving end would be heart-broken. Hard hit by words, he will be in constant sorrowful mien day and night. The sorrow would even be deeply etched in his heart. Hence, nobody should wound others with shafts of sharp words.
That is why the Sastras stress that man should have vaksuddhi (purity of speech) at all times. In fact, a wound caused by an arrow will soon heal; even a tree in the forest axed down might grow again, but a heart impaled by harsh words will not heal.
We bless all to understand this clearly and avoid hurting others in any way.