Q: Hinduism is a religion where there is no encouragement for religious conversions as does Christianity and Islam. Why it so with the other two religions? Isn''t Abraham the same as Lord Brahma and Sarah as Devi Sarawati? Isn''t it that it seems a copyright with tailormade changes for Chritianity?
A: You are right in that Hinduism does not encourage conversion. Yet, this is not because Hinduism does not believe that being a Hindu is important. In fact, Hinduism makes the same basic assumption as other world views: that it is right and that eventually everyone will or should come to this position. The belief in reincarnation and the caste system that is integral to Hindu thinking assumes that the upper castes are nearing the destiny of moksha. The lower castes are still on the way. Foreigners are in some fashion included in the wide view of Hinduism, though generally farther away in the progress to moksha. That there is not a desire to convert does not mean Hinduism does not believe that its views are universal. The understanding for the reason why Hindus don’t try to convert is contained in the three major teachings of Hinduism: casteism, reincarnation, and karma. Each of these reinforce each other in the belief that all men are on a path—at varying distances from attaining release from samsara into moksha. So in a sense, Hinduism believes there is not need or fruitfulness to trying to convert someone.
A parallel could be drawn in the treatment of poverty. Poverty is seen as a person’s karma in Hinduism; relieving it is not particularly useful or helpful in the Hindu world view.
Let me give a brief explanation of the view of Jesus in order to help you understand the answer to your question. In contrast to Hinduism, Christianity believes that a person is born to live once, to die and then to stand in judgment before God. Jesus taught the equality of all people and the need to love one’s neighbor, to have compassion on the poor, etc. These are all acts of free agents/creatures who will be held accountable for their deeds and thoughts. The presence of poverty and trouble in the world is due to human sin and rebellion. Jesus came to offer Himself as a payment for our sins as the only hope for men’s souls to be made right with God.
To die outside the belief system of Hinduism is not a threat or concern to Hindus, because they believe that these people will be born into this universe in another life in another form. Eventually, if a person lives right, they will ascend through the different forms of life to humanity and then to a high caste and then eventually reach moksha. To try to convert someone to Hinduism has no urgency. Karma will take care of all things in the Hindu view. In an sense Hinduism is saying “Why convert others to Hinduism—for we believe everyone is already a Hindu, even though they may not know it or confess it in this life.” In contrast to this, Jesus commanded compassion and work to free captives, to help the poor, and to proclaim forgiveness of sins to all people of the world. There is a definite urgency in the Christian world view. There is a recognition that there are those who are right with God through the forgiveness of Jesus and those who are not.
Regarding your question about Abraham and Sarah being Brahma and Saraswati... I have never heard this claim. The time periods and geographical locations of Abraham and Sarah from India are so vast and the beliefs they held so different from Hinduism that it is very hard to sustain this claim. It might be good for you to read the actual account of Abraham in the Bible for yourself to see the vast differences. Because Hinduism sees the world from a Hindu viewpoint, the other religions of the world are often equated with some Hindu God. This is a perfect explanation for why Hindus don’t try to convert people. They don’t need to do this in their worldview. Yet they have done essentially the same thing by converting the gods and the beliefs of other people into Hinduism: e.g. Jesus=Krishna, Abraham=Brahma. In the case of Christianity there is the belief of offering the opportunity to believe to everyone person (forceful conversion is something not only wrong but viewed as impossible in the Bible). This is because they believe that Christianity is true for everyone.
I suppose we could say, ‘Hinduism often converts the religions and views of others into a subsystem of Hinduism.’ Christianity does not see other religions as a subsystem of Christianity, but believes in offering every person the opportunity to believe in Christianity.