Parsha Blog

10 Amot Tall

February 5th, 2007 by Yaakov Ellis

Rav Ally wrote about the Netziv’s explanation for why Moshe had to sit down in order that Aharon and Chur hold his arms (since we would have thought that Moshe would have remained standing). The answer given is that since according to Chazal, Moshe was 10 amot tall, he had to sit down in order for Aharon and Chur (who were presumably of a more regular height) to be able to reach up high enough to support his arms.

I decided to take a closer look into the exact measurements involved in this scenario.

According to Wikipedia, from the ground to a person’s knees is 25% of their height, and from their knees to their waist is another 25% of their height. So when a person sits down (assuming that they sit on a surface so that their knees can bend at a 90 degree angle), their total height is 75% of what it originally was (since their upper-legs are know parallel with the ground. Additionally, the middle of a person’s chest (equal to where there arms are) is 75% of their height. After they are sitting down, this makrs 67% (2/3) of their height.

If we take Chazal’s statement of Moshe’s height at face value (and not as some sort of allegory), this means that when he was sitting down, his head was now 7.5 amot off of the ground (10 * 75% – approximately, assuming that Moshe’s body proportions are the same as everyone else’s), and his arms were approximately 5 amot off the ground (7.5 * 67%).

If we say that an Amah is 48cm (6 tefachim x 8cm per tefach), this means that when sitting, a 10 amah tall Moshe had his arms 2.4 meters (7.9 feet) off the ground. This means that in order for Aharon and Chur (not Yehoshua, who was leading the battle, 17:9-12) would need to reach (with some strength, since they were holding the position for hours) in order to hold up Moshe’s hands was nearly 8 feet off the ground. And this is just in order to have Moshe’s arms at shoulder level. If they wanted to hold Moshe’s arms above shoulder level (as the passuk implies that they may have done), then they would need to be able to reach even higher.

After some more calculations (a person can reach to approximately 125% of their height if their arms are vertical), this means that Aharon and Chur would have to be (at a minimum, approximately) 1.92m tall (6.3 feet, 4 amot) in order so support Moshe’s hands at a horizontal, shoulder-height (assuming that their arms were vertical). In order for Aharon and Chur to both hold up Moshe’s arms above his shoulder level, and do so by supporting his arms away from the bicep/shoulder area (since that would be the most difficult spot to support his arms, given the mechanics of the situation), they would have to have been even taller that 1.92m.

So, this explanation of the Netziv is supported by the fact that Aharon and Chur could have been very very tall (but within the normal range of human height, at least for NBA players) and still have been able to support Moshe’s arms when a 10 amah tall Moshe was sitting.

Alternatively, we could take the 10 amot height of Moshe as being allegorical and not literal, since it is physically impossible for the human body as we know it to support a body that is 4.8 meters tall (15 feet), and simply say that Moshe was sitting down because he was tired, and by sitting down, he made it easier for Aharon and Chur to hold his hands up as far above his head as possible.

(Of course, this raises the whole discussion of whether or not we are to take statements of Chazal like “Moshe was 10 amot tall” as being literal or allegorical, whether we need to believe as a principle of faith that the main figures in the Chumash were like super heroes, or whether they were ordinary humans, and whether or not it is legitimate to apply modern scientific knowledge to statements of Chazal rather than relying on the assumption that meshaneh haTeva – the nature of the world has changed. But all of that is beyond the scope of this post).