Coat of mail - Or “breastplate of scales.” A kind of metal shirt, protecting the back as well as the breast, and made of scales like those of a fish; as was the corselet of Rameses III, now in the British Museum. The terms, helmet, coat, and clothed (armed the King James Version) are the same as those used in Isaiah 59:17.
Five thousand shekels - Probably about 157 pounds avoirdupois (see Exodus 38:12). It is very probable that Goliath’s brass coat may have been long preserved as a trophy, as we know his sword was, and so the weight of it ascertained.