The importance of the Shar'iah

Q: 

  1. What is the importance of Islamic shariah?
  2. If a muslim says "what is shariah (as if he/she wants to comment that shariah has no importance) then what is comment as an Islamic Scholar.
  3. What if a muslim says some thing which is not in accordance with the Shariah rules of Inheritance?
  4. A muslim says that I cannot ask for my father's inheritance property because my mother and brother has taken care of that property. Please comment according to shariah.

Deriving benefit from the bank

Q: A person chooses to deposit his additional cash in the bank for safe keeping due to safety concerns. He has no intention of loaning these funds to the bank. Will these funds still be treated as a loan to the bank if he has no intention of loaning it to the bank at the time of depositing?