Genesis 6 King James Version (KJV)
6 And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them,
2 That the sons of God saw the daughters of men that they were fair; and they took them wives of all which they chose.
3 And the Lord said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years.
4 There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.
5 And God saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually.
6 And it repented the Lord that he had made man on the earth, and it grieved him at his heart.
7 And the Lord said, I will destroy man whom I have created from the face of the earth; both man, and beast, and the creeping thing, and the fowls of the air; for it repenteth me that I have made them.
8 But Noah found grace in the eyes of the Lord.
9 These are the generations of Noah: Noah was a just man and perfect in his generations, and Noah walked with God.
This is important to understand because it is the reason for the flood. Giants were not part of God's plan but the result of the fallen angels' actions. "and also after that" is referring to the reoccurrence of giants after the flood. There are many theories how they came back but that is not the point of this post.
What I want you to know is God is not capricious! He didn't cause the flood for no reason and he did not command the Israelites to wipe out entire communities for no reason. He did those things to rid the earth of anything He did not create. The giants were a result of the fallen angels mating with humans. The tribes He wanted off the earth also were giants or had some part of the blood or DNA of the fallen angels. I don't know why they are called fallen, they chose to leave heaven with Satan. It is thought that Noah and his family did not have mingled blood and that is what "perfect in his generation" means. Forgive me for not getting into the Hebrew definitions but I doubt you care anyway.
The book of Enoch is not in the Bible, but it addresses all of this and is very interesting. I think everyone should read it, especially Christians. It is very long so I listen to it from Youtube with my eyes closed. I highly recommend that because the beginning goes on and on about the movement of the heavens. The very first line is "This is written to the inhabitants of the earth in the end of days." Not verbatim but to that effect. Christian or not you may be feeling like something irreparable is happening in the earth, in people, and you are right! The Bible explains a lot as well as the book of Enoch. I always recommend reading the owners manual. Why go through the school of hard knocks when you can sit on your butt and learn from other peoples mistakes. The new testament says the old testament is "written for our admonition." You can learn a lot about the nature of God by reading how He interacted with people in those old testament books. You will be amazed how different the stories are from what you learned in Sunday school.
I hesitate to tell people these things because ignorance is bliss. I also don't relish being called crazy! However, I figure there are people who want to know what has changed and why. About a quarter of the Bible is prophecy so if you want to know what is and what will be, you can. It's an endless adventure! I for one do not like surprises and would rather know what is coming. There is some debate among Christians about whether or not we will be left here to see the worst of it: I refuse to enter that argument. People are supposed to be able to tell we are Christians by how we love each other and that argument tends toward viciousness so I'll pass.
Please comment with any questions you may have and I will try to answer. If it is a long explaination I will make a post of the answer. All photos are from Pixabay