Thank you for the question, “Why does god continue to allow Satan and demons to live, but has no issue with wiping out millions of humans in a biblical flood?”
I believe many readers of the Bible know the answer for God’s judgment on destroying all humans except 8 in the Flood and the end judgment of Satan and his followers.
As one reads Genesis 6:5, one reads the reason why God brought forth the Flood. The text says this, “5 The LORD saw how great the wickedness of the human race had become on the earth, and that every inclination of the thoughts of the human heart was only evil all the time” (NIV). The reason is that human was being vicious and wicked toward other humans and in their hearts they plotted what can do next to take what was others to be their own. There was no moral compass for mankind as each person do what he thought and wanted for him/herself. The victims cried out to the Creator God for justice or punishment against the perpetrator. God did not destroy good people, but wicked people, not just one sin or a few incidental wrongs, but a multitude of wickedness.
If God didn’t bring about justice on the earth, what will the victims say about God? Did the people during the Flood fear God’s judgment at all? Could it be that they didn’t believe that he existed, was powerless to do anything about it, or wouldn’t do anything about it? How wrong they were and despite their wickedness, God gave them time to repent as the Ark was being built. As one looks at our world and our culture, haven’t we come close to being like those who lived before the Flood? In my opinion, we are behaving much like those days where victims cry out for justice to God since justice was denied on earth.
As one reads the Book of Revelation, one reads that God will judge Satan and the demons. They do not get a free pass without penalty for their disobedience to God. Satan and his demons do not force anyone to be wick, but they tempted individuals to carry out their own selfish desires. No one has to drive over the speed limit, but our selfishness and desire to get their sooner may lead one to drive more recklessly with one’s car.
Revelation 20 says this, “10 And the devil, who deceived them, was thrown into the lake of burning sulfur, where the beast and the false prophet had been thrown. They will be tormented day and night for ever and ever” (NIV).
Satan’s actions will not be excused by God. He will not let him and his demons get away with it. There is a coming judgment for them in the Lake of Fire forever and ever. There is no redemption for them. Every evil creature will be judged for their attitudes and actions before God.
SUMMARY: God brought forth justice on the individuals by the Flood and will bring forth justice on Satan and his demons at the Great White Throne Judgment. The final judgment awaits every evil creature under heaven.
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