What is the significance of praying for the dead and lighting lamps in Buddhism?

Each of us is dragged down by karma, so The six great divisions in the wheel of karma suffers from all kinds of troubles. All karma comes from karma, and good and evil are good and evil from karma. For example, a person dies because his karma is deep and he is dragged into hell by karma. However, no matter how big the karma is, it is not as strong as expected. Intention can destroy karma. For example, the earth treasure bodhisattva made a wish to her mother and destroyed her karma. Therefore, we pray for our loved ones, which is not only a kind of sustenance and hope, but also to eliminate karma for the deceased relatives.