But where does that come from? כתנת means a cloak, but כתנת פסים only occurs here and when it is taken from him:
And in the story of Amnon and Tamar:
JPS tranlates כתנת פסים as “an ornamented tunic”, with the footnote: “Or ‘a coat of many colors’; meaning of Heb. uncertain.”
The earliest translation of “multicolored” I can find is from the Septuagint:
But even there, the Greek word ποικίλον means “varied”. Nothing about colors.
The clue is the only use of the singular, and in Aramaic:
פס יד is the palm of the hand, and in Gemara Aramaic it is used for a part, and thence means “stripe”. So כתנת פסים means “a coat made from pieces”, “a striped coat”.
“כלי מילת” in the gemara refers to a fine woolen garment (irrespective of its color), and that’s how Rashi translates it, with a reference to מגילת אסתר:
But that’s all pretty far from פַּס יְדָה, the palm of the hand. So the midrash (ironically) takes the word more literally:
In the story of Tamar, Malbim says that it was delicate enough that it was an indoor garment only. Throwing Tamar out clad only in her כתנת פסים is even more humiliating.
The idea that the כתונת is an undergarment is hinted at in the Yosef story as well:
Looking at it this way
changes our understanding of the כתנת פסים. We often think of it as a symbol that Yaakov is putting Yosef in charge of his brothers. A superfluous brightly colored garment is often a symbol of authority; think of who wears a tie in a factory. But in תנ״ך, it’s not a tie or a כתנת. It’s an אפוד.
The כתנת פסים is different. Whether we translate פסים as “delicate” or “long-sleeved”, it is a garment worn by someone who did not engage in manual labor. The other brothers were mucking about with the sheep. Yaakov, by dressing Yosef in a כתנת פסים, was saying that Yosef didn’t have to get himself dirty.
So what was Yaakov thinking? We have to go back to the original pasuk:
What is a בן זקנים? Literally it means “a child of his old age”, but all 11 sons were born in a 7-year span; Zevulun is the same age as Yosef. Why is Yosef the בן זקנים? Onkelos reads זקן as figurative:
And this gets back to my favorite pasuk in the Torah:
יושב אהלים has two meanings:
Is Yaakov a shepherd or a scholar? Yes.
Yaakov has two legacies that he wants to pass on to his children. There is the family business:
And the real family business:
Yaakov saw in Yosef the potential to be the one to lead ושמרו דרך ה׳ לעשות צדקה ומשפט. But Yosef missed the point:
He will eventually get there and become יוסף הצדיק. But he’s not there yet.