[Ali Imran]

Example 
You want to form a family to fill your house with joy and laughter
Kids running about calling u papa hug you with love 

But u worried they disobey u so warned them don’t play with the sword or will kill you
But your children disobey and start to fight each other with the sword and got injured and blood gushes out from their body 
In order to save them u have to transfuse blood to save them
because u love them

This is not an example. This is Christianity. 

God cannot tolerate mankind sinning but God creates mankind with the propensity to sin. And then God propose a solution that is illogical, irrational, cruel and unjust in order to correct that problem. 

We must believe that or God will throw us in hell.

You believe that because you fear what's on the other side and Christianity offers a comfort for that fear.