Sforno on Deuteronomy 3:11/ספורנו על דברים ג׳:י״א

1באמת איש; according what the Refaim had adopted as their standard cubit, i.e. a much longer one than that of average sized citizens. Such subjective, as opposed to standard. measurements, are mentioned in Isaiah 56,11 where the prophet speaks of איש לבצעו מקצהו, “every one has done his own thing.” The word איש also occurs describing such individual feats in Kings I 20,20 ויכו איש אישו, “each man struck the opponent facing him.” There are other verses in which the word איש does not mean “man,” but is a simile for the individual nature of something, No doubt there were many “cubits” other than the one described here as 9 times the length of the cubit of an average sized individual. The reason the Torah relates this historically hardly important information is to impress the reader with the extraordinary size of these Refaim. The strength of such giants can be imagined once we are aware of their size. The fact that the Ammonites had been able to defeat a nation whose warriors were of such proportions gives us a clear indication that it must have been G’d’s will that they were able to do so. (compare our commentary on 2,21).