We all know that a baby and its mother are connected to each others' bodies with an umbilical cord while in the mother's womb and is disconnected/cut when the baby is born. The same phenomenon applies to one's spiritual birth, but in direct contraposition.

When we are born into this material world, this physical "umbilical cord" is disconnected - however, a spiritual cord (a Silver Cord), which is invisible in this dimension, links one with the spiritual world (subconscious mind universe) and allows us to receive light (universal) energy (just as a baby in the uterus is fed through a physical umbilical cord). This spiritual cord becomes thicker and nurtures us - the better to allow life's energy to more easily flow into you as you continue raising your spiritual level by acting under the law of Spiritual Ethics (the law of nature), which leads to the exquisite circulation system of balanced co-existence.

When one dies, this spiritual cord disconnects (just as the umbilical cord disconnected at birth) and you thus return to the subconscious world.

People who possess higher frequency spiritual vibrations are often said to possess a higher spiritual level.
A higher spiritual level person is not necessarily materialistically successful, well-known or highly placed in society although they may possess those qualities in the physical world. A true highly spiritual person will help others no matter what his situation may be (unconditional love). Even if he is poor, he gives what he has in the belief that it will help others. Even if he is humiliated or challenged, he prays for peace in the others' mind with unconditional forgiveness..

In this material world, one's power is very self-centered and has its limits. For example, while rich and financially powerful, you have power as long as  it is maintained. However, when you lose that wealth, your power which had been merely focused and based on material wealth also disappears. Likewise, if your focus were on your ego-based desires, such as a man with higher status within a society or a young good-looking female, when that person loses his status and wealth or the woman becomes old and loses her youthful appearance, their attraction will be lost as is the energy focused and directed toward non-perpetual issues.

Therefore, it means that relying on ego-based interests will eventually make you fearful of facing forthcoming material limits. Since we are getting our life energy (love energy) while living in this material world through this silver cord, we should eliminate all obstacles (our egoistic thinking based on selfishness) and receive the optimal level of  the unlimited life energy from one's link with the silver cord.