1 Samuel 17:5

17:5 He had a bronze helmet on his head and was wearing scale body armor. The weight of his bronze body armor was five thousand shekels. ¹ 

1 Samuel 17:38

17:38 Then Saul clothed David with his own fighting attire and put a bronze helmet on his head. He also put body armor on him.

[17:5]  ¹ sn Although the exact weight of Goliath’s defensive body armor is difficult to estimate in terms of modern equivalency, it was obviously quite heavy. Driver, following Kennedy, suggests a modern equivalent of about 220 pounds (100 kg); see S. R. Driver, Notes on the Hebrew Text and the Topography of the Books of Samuel, 139. Klein, taking the shekel to be equal to .403 ounces, arrives at a somewhat smaller weight of about 126 pounds (57 kg); see R. W. Klein, 1 Samuel (WBC), 175. But by any estimate it is clear that Goliath presented himself as a formidable foe indeed.