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.
According to our purpose, Motivation & Sincerity Krishna reveals himself to us.
Knowledge of Scriptures is Transcendental. Knowledge of Books of this World is Material.
The causeless mercy of Lord Vishnu is unparalleled, and such mercy is perceived by the devotees only by the grace of the Lord.
Srimad Bagavatam 1.6.31,