Even in Abraham's time, the giant tribe of Rephaim was living in Bashan (Gen 14:5). But out of the remnant of these, king Og, whom the Israelites defeated and slew, was the only one left. For the purpose of recalling the greatness of the grace of God that had been manifested in that victory, and not merely to establish the credibility of the statements concerning the size of Og (“just as things belonging to an age that has long passed away are shown to be credible by their remains,” Spinoza, etc.), Moses points to the iron bed of this king, which was still in Rabbath-Ammon, and was nine cubits long and four broad, “after the cubit of a man,” i.e., the ordinary cubit in common use (see the analogous expression, “a man's pen,” Isa 8:1). הֲלֹה, for הֲלֹא, synonymous with הִנֵּה. There is nothing to amaze is in the size of the bed or bedstead given here. The ordinary Hebrew cubit was only a foot and a half, probably only eighteen Dresden inches (see my Archäologie, ii. p. 126, Anm. 4). Now a bed is always larger than the man who sleeps in it. But in this case Clericus fancies that Og “intentionally exceeded the necessary size, in order that posterity might be led to draw more magnificent conclusions from the size of the bed, as to the stature of the man who was accustomed to sleep in it.” He also refers to the analogous case of Alexander the Great, of whom Diod. Sic. (xvii. 95) affirms, that whenever he was obliged to halt on his march to India, he made colossal arrangements of all kinds, causing, among other things, two couches to be prepared in the tents for every foot-soldier, each five cubits long, and two stalls for every horseman, twice as large as the ordinary size, “to represent a camp of heroes, and leave striking memorials behind for the inhabitants of the land, of gigantic men and their supernatural strength.” With a similar intention Og may also have left behind him a gigantic bed as a memorial of his superhuman greatness, on the occasion of some expedition of his against the Ammonites; and this bed may have been preserved in their capital as a proof of the greatness of their foe.
(Note: “It will often be found, that very tall people are disposed to make themselves appear even taller than they actually are” (Hengstenberg, Diss. ii. p. 201). Moreover, there are still giants who are eight feet high and upwards. “According to the N. Preuss. Zeit. of 1857, there came a man to Berlin 8 feet 4 inches high, and possibly still growing, as he was only twenty years old; and he was said to have a great-uncle who was nine inches taller” (Schultz).)
Moses might then refer to this gigantic bed of Og, which was known to the Israelites; and there is no reason for resorting to the improbable conjecture, that the Ammonites had taken possession of a bed of king Og upon some expedition against the Amorites, and had carried it off as a trophy to their capital.
(Note: There is still less probability in the conjecture of J. D. Michaelis, Vater, Winer, and others, that Og's iron bed was a sarcophagus of basalt, such as are still frequently met with in those regions, as much as 9 feet long and 3 1/2 feet broad, or even as much as 12 feet long and 6 feet in breadth and height (vid., Burckhardt, pp. 220, 246; Robinson, iii. p. 385; Seetzen, i. pp. 355, 360); and the still further assumption, that the corpse of the fallen king was taken to Rabbah, and there interred in a royal way, is altogether improbable.)
“Rabbath of the sons of Ammon,” or briefly Rabbah, i.e., the great (Jos 13:25; 2Sa 11:1), was the capital of the Ammonites, afterwards called Philadelphia, probably from Ptolemaeus Philadelphus; by Polybius, Ῥαββατάμανα; by Abulfeda, Ammân, which is the name still given to the uninhabited ruins on the Nahr Ammân, i.e., the upper Jabbok (see Burckhardt, pp. 612ff. and v. Raumer, Pal. p. 268).