Sheikh Salman al-Oadah
On one occasion, the Prophet's wife Hafsah chided her co-wife Safiyyah by calling her “the daughter of a Jew”. She started to cry.
The Prophet (peace be upon him) then came in and asked her why she was crying. She said: “Hafsah called me the daughter of a Jew.”
To this the Prophet (peace be upon him) replied: “Verily, you are the daughter of a Prophet, your uncle was also a Prophet, and you are the wife of a Prophet, so what does she have over you to boast about?”
He then turned to Hafsah and said: “Fear Allah, O Hafsah.” [Sunan al-Tirmidhî (3862)]
[This hadîth is authentic. It has been determined to be authentic by al-Albânî in Sahîh wa Da`îf Sunan al-Tirmidhî (3894) and al-Mishkât (6183).]
Safiyyah's statement was true, because Safiyyah’s father, Hubayy b. Akhtab, was in fact a Jew who had died without ever accepting Islam. Still, such a comment was meant as a take on Safiyyah’s person, which was only more hurtful as it was coming from her co-wife.
Safiyyah was a descendant of Aaron (peace be upon him). So, when Hafsah insinuated that Safiyyah’s being of Jewish descent was something bad, the Prophet (peace be upon him) showed Hafsah another way of looking at it: that Safiyyah was the descendant of Prophet Aaron and that her uncle was Moses, and that her husband was Muhammad (peace be upon them all), so there was no reason at all for her to be ashamed of being of Jewish descent.
Source: Islam Today