We should never ask God for anything except moksha. It is not right to make demands of God. What we suffer in life is the result of our karma, and we cannot escape the consequences of our karma. V.S. Karunakarachariar narrated, in a discourse, an episode in the life of Appayya Dikshitar to show how great men accept their lot without complaining.
Appayya Dikshitar suffered from an unbearable stomach pain. But he did not want to cancel the classes for his students. He was also particular that his teaching should not be compromised because of his pain. So he took some grass and transferred his pain to the grass and taught the students. At the end of the classes, he transferred the pain back to his stomach.
Noticing this, one of his students asked Dikshitar why he did not take a bigger clump of grass and transfer all his pain to it once and for all. Dikshitar replied that his stomach ache was the result of his past actions. He had to pay for all his acts of omission and commission. So it was only proper that he pay for his karma.
Bhishma prayed that he should face in this janma itself the consequences of all his karma in all his previous births, so that when he departed from this world, he would go to God with a clean account. There would be no deficits to be carried over to another birth; there would be no need for another birth. It takes a lot of courage to speak as Bhishma did.
We would be afraid to make such a request to God, for we do not know what sins we would have committed in previous births and we would, therefore, be scared of what we might have to face. But whatever the consequences, we have to face them sooner or later. There is no running away from these consequences. Bhishma knew this, and so he prayed that his karma be wiped out in this janma itself.
When all the Gopikas ran out on hearing flute notes played by Lord Krishna , one alone was denied permission by her mother-in-law.
Shocked at this separation from Krishna, she died at once. But the real reason is that her karma meant she had to die then.