You are driving car, running with seventy miles speed.. it is smashed accidently. But you are alive then you have to change your car. Similarly, we can drive this machine called the body for so many years; then it becomes old and we have to change it for another machine. This is the process of birth and death.
Water is very clean. When it rains from the clouds it is very clean, but as soon as it drops on the ground it becomes muddy. So that muddiness has to be cleansed then water will come out again clean. Similarly, our consciousness is clean, but because it is contaminated with the muddy things of the material nature, it is cloudy.