Acharya Prashant explains that security exists on two levels: the core and the physical. At the core, the heart or soul is eternally secure and cannot be diminished. However, as human beings, we also exist as bodies and minds, which require their own forms of security. Physical security involves providing for basic needs like food, clothing, and shelter, while mental security requires knowledge and information to navigate the world without confusion. He emphasizes that even great saints required basic sustenance, and knowledge is essential to avoid living in a state of constant bewilderment about the natural world.