Genesis 6: 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.
It was from Cain that the giants descended, for we learn in Genesis 4: 15 that God set a mark upon Cain. This mark was his body being changed to a colossal stature and a dreadful/intimidating look to strike fear into any opponent who would dare confront him. The Bible tells us quite plainly that giants existed before the Flood (“…in those days…”) and after the Flood (“…and also after that…”). Indeed, as we read through the scriptures, we find multiple accounts regarding men of giant stature, and how that even the Israelites were intimidated by them when the land of Canaan was spied out (Numbers 13: 32 – 33: And they brought up an evil report of the land which they had searched unto the children of Israel, saying, The land, through which we have gone to search it, is a land that eateth up the inhabitants thereof; and all the people that we saw in it are men of a great stature. And there we saw the giants, the sons of Anak, which come of the giants: and we were in our own sight as grasshoppers, and so we were in their sight.).
The famous Goliath of Gath was of a height exceeding nine-feet (1 Samuel 17: 4). Og of Bashan’s bed was about 13-feet long and over six-feet wide, a testament to his great stature (Deuteronomy 3: 11). Even David and his mighty men fought Goliath’s gigantic brothers in 2 Samuel 21. Furthermore, excavations around the world have unearthed skeletons and their tooling belonging to men of great stature, whose average height exceeded 14-feet! These were big burley men, of formidable physique and sharp intelligence, not as the fairy tales depict them, being dumb brutes of simple minds.
The intermarriages between the men of Adam’s lineage and the women of Cain’s lineage (described in Genesis 6: 2, 4) did produce giants, but they were of a lesser degree than the thoroughbred giants whose parentage was Cainite on both father and mother’s side. This is because the men of Adam’s lineage were of ordinary stature, whereas the women whom they went with of Cain’s lineage were the carriers of giant genetics and were of large stature themselves. We also understand that these giants were not a product of sexual encounters between angels and human beings as some claim in their interpretation of Genesis 6: 2, for no person in the Bible who saw an angel ever reported the encounter as being a visitation from a gigantic supernatural being. Indeed, the Bible tells us in Hebrews 13: 2 that angels have been entertained unawares, proving that angels are of ordinary stature.