Why did God send a worldwide flood?

Was it because of man's sin, or something totally different?

Well, in Genesis 6, we read that the sons of God aka fallen angels came down and mated with the daughters of men, and the women bore children to them, creating a GIANT race. It obviously killed the women when they gave birth to them.

"There were giants on the earth in those days, and also afterward, when the sons of God came in to the daughters of men and they bore children to them. Those were the mighty men who were of old, men of renown." (Genesis 6:4)

Fallen angels were also teaching human beings wicked things like teaching women how to kill their own offspring from their wombs, and teaching men war. They created unnatural, abominable creatures by manipulating and mixing the DNA of God's creatures with other creatures, basically making hybrid creatures. Human beings were mixed with animals, and animals mixed with plants. Fallen angels were trying to corrupt God's creation, which is why God wanted to start over by washing everything corrupt away. Those same fallen angels are imprisoned in eternal chains under darkness until the day of redemption, and the saints(believers) will be the ones to judge them.

"And the angels who did not stay within their own domain but abandoned their proper dwelling—these He has kept in eternal chains under darkness, bound for judgment on that great day." (Jude 1:6)

"Do you not know that we shall judge angels? How much more, things that pertain to this life?" (1 Corinthians 6:3)

The Bible says, Noah and his family were perfect in their generation, meaning, they weren't genetically corrupted. Noah was a drunkard, he did sinful things, but God still favored him because of his faith, and he simply trusted God, and never questioned God about the flood, but simply believed and accepted his quest to build an ark.

God told Noah to warn the people in the city to come into the ark so that they would be physically saved and not die. Notice how God didn't point out their sin, He simply offered them to enter into the ark to be saved. Physical salvation was offered to everyone, but not everyone believed and trusted in the ark to save them because, they did not believe that a flood would come to a desert, until it was too late. After God, Himself shut the door, it was too late to climb in and be saved, but instead, they died because of their own foolishness.

The Ark represented Jesus, our Eternal Salvation for our souls, He is offered to everyone, but not everyone believes there will be a Lake of Fire, and only those who simply believe, rest, and trust in Him as their personal Savior, will be saved from eternal death for their souls.

And, just as in the days of Noah, hybrid creatures are being made in laboratories, cloning is happening, we see abortions happening, wars, violence, sexual immorality, drinking, people acting like the world is never coming to an end, just going about their daily routines, and everything else that was going on in the days of Noah, AND Lot.

But, you see, even those sins were forgiven and paid for at the cross, the very moment Jesus shed His blood. It's not too late to enter into the Ark, but don't wait for tomorrow, today is the day of salvation. All you have to do is believe you are forgiven, that Jesus died for your sins at the cross, that He was buried, and rose from the dead on the 3rd day! And, simply put your trust in Him as your personal Savior, and rest in Him. Allow Him to change your behaviors and actions.

Enter into the Ark before it's too late, before God shuts the door, and eternal death awaits.