Anyone with a material body cannot remember his past life, nor can he foretell his future life, nor can he predict the outcome of his present life; therefore he cannot know what is happening in past, present and future. A person in the mode of ignorance and interested only in his present body is like an animal, for an animal, being covered by ignorance, thinks that the ultimate goal of life and happiness is to eat as much as possible. A human being must be educated to understand his past life and how he can endeavour for a better life in the future. Unless one is liberated from material contamination by devotional service to Lord Krishna, he cannot know past, present and future.
Krishna is the perfect knower of past, present and future. In the beginning of the Bhagavad-gita, the Lord said that all living entities existed individually in the past, they exist now in the present, and they continue to retain individual identity in the future, even after liberation from the material entanglement. So He has already cleared up the question of the future of the individual living entity.
Therefore the verdict of Krishna is the final and complete answer to all doubts, because He knows past, present and future perfectly – but no one knows Him. Krishna and Krishna conscious devotees alone can know what is what.