Commentary for Genesis 37:31

שעיר עזים A KID OF THE GOATS — its blood resembles that of a human being (Genesis Rabbah 84:19).

וישחטו שעיר עזים, they said that its blood resembled the colour of human blood.

שעיר עזים, “a male goat; ”according to Rashi they chose this animal as its blood most closely resembles the colour of human blood. When we read in the Talmud Gittin, folio 57, where the Babylonian general Nebuzaradan is reported of having tried to compare the blood of the hundreds of thousands of Jews he had slain in Jerusalem to that of the prophet of the prophet Zecharyah which had not stopped bubbling after having been stoned inside the Temple (he was also a priest) for having rebuked King Joash (about 150 years before the Temple was destroyed) and having failed to prove that that blood was human blood, we must assume that this was due to Zecharyah’s blood having become contaminated during all those years.

הַכֻּתֹּנֶת THE COAT — This is the form of the noun in the absolute state, but when it is in the construct state — as e.g., Joseph’s coat”, “the coat of many colours”, “the coat of linen”, — it is punctuated as כְּתֹנֶת.