출애굽기 18:9의 주석

ויחד יתרו AND JETHRO REJOICED — This is its literal meaning. A Midrashic comment is: his flesh became full of prickles (חדודין — his flesh crept with horror) — he felt grieved at the destruction of Egypt. That is what people say (what the common proverb says): A proselyte even though his heathen descent dates from as far back as the tenth generation, do not speak slightingly of an Aramean (any non-Jew) in his presence (Sanhedrin 94a).

ויחד יתרו, he did not rejoice over the destruction of Egypt as a major power. This is what he should have done if he had been truly concerned with the honour and glory due to his Creator. We know this from Psalms 58,11. However, he did rejoice over the well being of the Israelites. He behaved like someone whose heart is moved by the tears of the oppressed.

ויחד יתרו על כל הטובה, Yitro rejoiced over all the goodness, etc." Onkelos translates the word ויחד as וחדי, the aramaic word for "he was glad." Why did the Torah have to use an aramaic word in this instance instead of using a Hebrew word familiar to all of us? Although we learned in Sotah 32 that certain sections of the Torah may be read publicly in any language, we still need to know why the Torah chose an aramaic expression here in the original.