Giants also existed after the entire world was flooded with water. The first mention of such people is in the book of Numbers. Ten of the twelve men Moses sent to spy out the promised land reported seeing huge people known as the children of Anak (the Anakim). Only Joshua and Caleb had enough faith to report that, no matter who was in Canaan, that God would help his people take over the land he had promised them (Numbers 13:30, 14:6). It was Israel's faithlessness, and fear of the giants in the land of milk and honey, that caused them to wander the wilderness for forty years (see Numbers 14).
And they brought up an evil report of the land which they had scouted out to the children of Israel, saying, ' . . . And all the people whom we saw in it were men of great stature (giants) . . . And we were in our own sight like grasshoppers (Numbers 13:32 - 33, HBFV)
The Israelites, while wandering the wilderness for forty years, encountered a second group or race of giants led by Og, king of Bashan, who lost a battle against them (Deuteronomy 3:11). The King was an enormous man, sleeping in a bed 9 cubits long and 4 cubits wide. If we assume a conservative value of 18 U.S. inches to a Biblical cubit, Og's bed was 13 1/2 feet long (4.1 meters) by 6 feet (1.8 meters) wide! For comparison purposes, the most common large mattress in the U.S., the "king size" mattress, is 6.6 feet long (2 meters) by 6.3 feet wide (1.9 meters).
The third mention of very large people in God's word is within the well-known story of a young king David fighting Goliath the Philistine. Goliath was one of several tall and strong Philistines. Scripture states that he was six cubits and a span tall (1Samuel 17:4). The length of a span is likely to have been around 9 inches (22.9 centimeters). If we also use the conservative length of a cubit mentioned above, Goliath was at least 9 feet 3 inches tall (2.82 meters) and possibly bigger!
Goliath was one of at least two giants, in the same family, who could wear a protective battle coat weighing more than 80 pounds U.S. while also carrying a massive 26 foot (7.9 meters) spear. The head of his spear was stated to weigh an amazing 17 pounds U.S. (7.7 kilograms)!
King David and his men encountered several giants, other than Goliath, during his life before and after being made King over Israel. One of them was named Ishbibenob, whom David killed with the help Abishai (2Samuel 21:16). Another was Saph, who was killed by Sibbecai during a battle between the Israelites and Philistines at Gob (verse 18). A third man of huge stature, who apparently liked to fight, was killed by Jonathan, a son of one of David's brothers, at a battle in Gath (verse 20). All told, the Bible records at least three groups or races of people who produced giants after the flood. They were the Anakim (children of Anak), the people of Bashan, and the Philistines (Rephaim).