Is it a correct practice?
Well it is correct if you want to weaken the sun. It's like asking the burning sun to cool down. It's equivalent to reducing the luster and gracefulness of the father of the creation. Particularly in the morning when sun is expected to bring new life on earth it is very dangerous to cool it down. Such a person who engages in this impious act would face miseries in abundance. Sun god and his defending sprits will harm him with all the possible means.
Sun is the natural karaka of Father, soul, intelligence, name and fame, respect and honor from king's court etc. Mark these words who so ever offer water to the rising sun would lose his name and fame and will get dishonor/fine/imprisonment from king's court.
Offering water to sun is not a remedy but it's a cheap trick to provoke the anger of the sun sprits. Anyone who performs such an act would face brutality from sun sprits. It will not benefit you in any ways; it will cause only harm to you and your family. Do you think's that any ordinary mortal would even dare to
provoke rage of Sun God. Don't even try to involve in such stupidity. Such reckless acts would destroy your lives into dirty obscenity.
Usually people are very egoistic and consider themselves as very intelligent that they consider it as a matter of pride to ignore the words of those who really know and understand. I sometimes laugh and even sometimes weep at their ignorance and misfortunes. No matter how rudely or politely you tell these people whatever they are doing is wrong and dangerous, they didn't listen until and unless they are hurt pretty badly by these nature laws. Some lucky ones did listen and save themselves from the downfall, some unlucky ones keep on repeating same mistakes over and over again and hurt themselves over and over again and still face people as life is under their control and they didn't need any help or guidance.
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In north India Brahmins perform fire sacrifices every morning to strengthen the Sun. Because of the tapo bala generated Sun has become so strong that it threatens the very existence of this universe. To save the world gods requested Sage Agasthya to travel to south India preach Brahmins there to quench the fire of Sun by offering it water every evening.
So it becomes a regular practice that Brahmin in north will strengthen Sun by performing fire sacrifice in the morning and Brahmin of south will cool it down in the evening by offering it water. Thus is the process world is saved from inhalation.
Time change, situation changes. Brahmins of north Indian were brutalized to not to perform fire sacrifices. Their religious texts was corrupted and purity of their bodies was destroyed by forcing them to consume various chemical and drugs. Thus they lost all their powers to perform effective fire sacrifices. But the Brahmin in south India continues to perform their water ritual to quench the fire of Sun.
Ancient ritual and practices are relevant for a limited time period they should be changes and modifies according to the needs of time. Sun is already very week and there is no need to weaken it further. A Ritual which is pious once upon a time has now become evil and anything which is weakening our very roots should be stopped.
I usually sit in meditation for prolong hours. During many sessions I subtly receive this message and day by day urge in me increase to share this. I don't care about name or reputation, all I care about is following my heart. Sharing this message has brought me tremendous peace and happiness.