Christians,can you please enlighten me on what this bible verse actually means...?

I think that is a reference to the Armegeddon. No one will be spared . after being a parent, you will understand that the worst way to hurt a man is to kill his children. It does not say that the children will be cast into hell, just that their flesh bodies will be killed in the mele. The innocent involved in that scurmish will most likely be saved. He loves the ones He loves and hates the ones He hates,