In Parshat Devarim, Moses reminds the Israelites how they easily defeated Og, the mighty giant, King of Bashan, who slept on an iron bed that was about 16 feet long (Deuteronomy 3:11). The purpose of Moses’ speech was to instill courage in the Israelites, for the Israelites not to be afraid since HaShem will be with them when they set out to conquer the land of the Canaanites.
The significance of Og’s bed is twofold: clearly its length tells of Og’s large size, attesting to the fact that Og was a powerful opponent. But what about the bed being made of iron? Nachmanides, 13th century commentator, the Ramban, states that ordinary wooden beds would not be strong enough to support Og and would break under his massive weight. I think there is another reason for the importance of an iron bed. Iron had to be extremely rare, more so than precious gold and silver. Iron was certainly less common than copper or bronze. There are no iron deposits in Israel or its surroundings. The question then arises as to what is the source of the iron for Og’s bed. The answer is that the iron for Og’s bed probably came from meteorites. As an indication of how rare iron was in ancient times, an iron sword, probably a cherished possession, was found in King Tut’s tomb (dating back about 3360 years ago) that is thought to be of meteoric origin. Interesting enough is that the Land of Israel is described in Deuteronomy 8:9 as a land whose stones are iron.
I would speculate that a meteoric origin for the iron of Og’s bed could have taken on a mystical significance as an object coming from the heavens as a gift from the gods and a token of power to the King of Bashan. Israel’s defeat of Og then also becomes a victory of HaShem over Og’s heathen gods.
 Early Near Eastern Steel Swords by Herbert Maryon, R. M. Organ, O. W. Ellis, R. M. Brick, R. Sneyers, E. E. Herzfeld and F. K. Naumann, American Journal of Archaeology, Vol. 65, No. 2 (Apr., 1961), pp. 173-184. Published by: Archaeological Institute of America. http://www.jstor.org/stable/502669