The fear of death is born with man, though this is the only thing that he knows is certain to happen to him. Attachment to material things makes man cling to life. When you chant the Name of the Divine, when you are one with the divine, you accept death. While you are attached to life and afraid of death, you die with that fear and that weight clinging to you. If you have attained liberation you are free from death (you accept the inevitable). You die without fear and by remembering the Name of God, your soul leaves the body free of that fear and attachment. If you are reborn, your soul is still free from that fear. If you die in "unity", you are free from rebirth, unless you will it.