Commentaire sur La Genèse 32:33

גיד הנשה THE SINEW OF THE THIGH-VEIN — Why is its name called גיד הנשה? Because it sprang נשה) and rose from its proper position. The word has the meaning of “springing”. Other examples are: (Jeremiah 51:30) “Their strength sprang away (נשתה)” and (41:51) “for God hath made all my trouble spring away from me נַשַּׁנִי)".

על כן לא יאכלו, as a reminder of the heroism displayed by Yaakov, as well as a reminder of the miracle that G’d performed for him as a result of which he did not die.

We find in [statements of] the Rabbis, may their memory be blessed, that deep things, the comprehension of which are difficult, are compared to tendons; as Rashi explained in Parshat Yitro (Exodus 19:3), s.v., and tell the Children of Israel (he explained, "[Tell] to the males, matters as difficult as tendons"). And comprehension is called eating; as we find that about the four that entered the 'orchard,' it cites the verse, 'eat your fill of honey,' about investigation that is hidden from 'the eye of all the living.' And this commandment is a hint for the [future] generations to prevent Israel from hidden (mystical) investigations; as [Ben Sira] said, "You have no businesses in hidden things." For one should be concerned [about this], lest their minds be destroyed and they come to heresy. As the many will not have the wisdom to understand the secrets properly, because their minds travel through the muddied valley. [This is] because the vanities of this world and its pleasures confuse the mind of man. And the hint in the prevention from eating the sciatic tendon for the generations is to be a commemoration that God prevented them from the fruit of the Tree of Knowledge, such that they not feed their minds things as difficult as tendons - as he [injured] the hollow of Jacob's thigh. And if this setback temporarily occurred to the perfect Jacob when he veered a little from the even path, what will the 'hyssop of the wall' (average people) - whose primary occupation is with the vanities of this world and its pleasures - do? Therefore they should not be occupied with hidden things, except for the special few, like R. Shimon Bar Yochai and his likeness - who become repulsed by, and renounce, the vanities of this world.