B"H
Where the Torah says (Breishis 32:24): "And Yaakov was left alone, and a man wrestled with him until the break of dawn," we have heard somewhat about this episode by way of an oral tradition, viz., why it was that our forefather Yaakov tarried behind. For he had gone back a short distance in order to retrieve the small flasks which he had left behind. From this incident our Sages teach us (Hullin 91.a) that the righteous hold their own personal possessions more dear unto themselves than their own physical bodies. And why? Because they do not gain what they own by theft, neither by brigandage, nor by purloining others!

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The Torah (Breishis 32:32) teaches us:
"Therefore will the children of Yisrael not eat of the sinew which shrank (displaced tendon), which is upon the cavity of the thigh, unto this very day."
By way of an oral tradition, it has been passed down unto us that the prohibition of eating the sinew or tendon applies to the two hindlegs of the animal that is to be eaten. Even to this day, the Yemenite Jews who are expert in the removal of all hard, white fat, or suet (Heb. "chelev"), found on the internal organs and hind parts of the slaughtered animal, abstain from eating these tendons by carefully having them removed. (Other communites forfeit the hind part altogether, choosing not to eat this part of the animal out of concern for their unintentional eating of "chelev," or thereby becoming liable to extirpation.) The tradition, however, still stands with a small minority. The sinew runs down the leg from the upper thigh bone, reaching as far as the feet. That which is required to be removed is actually all of the sinew (tendon) which is located on the upper thigh bone of both hind legs, as also the greater part of that which runs down the calf-muscle of both hind legs. It is a common practice among those expert in "nikur" (the removal of fatty tissue) to poke around the tendon with a knife, removing all excessive fat ("chelev") which he finds running parallel to the long sinew that is taken away. (This was made known to me by the ritual slaughter, Avidor.) The commandment to remove the sinew applies to, both, domesticated animals and to wild animals, but it does not apply to birds.

Sincerely,
David

B"H
Correction: Should rather be "Parashas VeYishlach."

Sorry, David

B"H
This week's Parasha, "Vayishlach," carries with it a moral lesson, viz., how that we are to impart some benefit upon the place where we live, by way of showing gratitute to all those that surround us and to those who are a part of our daily lives. The Sages learned this from our forefather, Yaakov. For when he had gone to the city of Shechem, it says of him, "Veyechan Eth Panei Ha-'Ir," which has the literal translation of: "And he camped at the outskirts of the city." The Sages, however, understood that the word "Veyechan" (Heb. ויחן) could also mean, "and he showed favor unto." Wherefore, by way of an exegesis, we learn that Yaakov reared up a stall in the city, and sold there sheep that had been slaughtered. Others say that he mastered the art of numismatics, and cast silver coins in specie bearing his image and which brought him quick fame.
Sincerely,
David

B"H
A slip of the keyboard. I should have written "gratitude."
David

The Gemarah is in Shabbos 33b. It also adds a third Shita that he built bathhouses. It brings there that R. Shimon B. Yochai took his example when he was delivered from the cave. See there.