One of the hardest things to explain to children, is how God has killed many people in the past, and will kill many people in the future, but He is still good.  Even as adults, we can struggle with this aspect of God.  I personally find this hard to grasp sometimes, and to explain.  It is probably something we will never fully understand until we are face to face with our Lord and Savior. I personally know many who profess to be a Christian, but really struggle with this aspect of God.  They struggle so much so that they have convinced themselves that parts of the Bible cannot be true.  The below are just a few examples of things people cannot believe are true.