Musar for Bava Batra 219:7

ויקח אהרן את אלישבע בת עמינדב אחות נחשון. The additional words "sister of Nachshon," prompted the Talmud in Baba Batra 110 to comment that before marrying a girl one should check out her brother's moral character.

However, our sages of blessed memory, who always instructed us and guided us on the paths of truth said: "love work and hate Rabanut" (Avot 1:10), and further "flay carcasses in the marketplace and earn wages and do not say, 'I am an important man, I am a Kohen, [and it is beneath my dignity]'." (Pesachim 113a), and further "one should always hire himself out to work which is strange to him rather than be dependent [on the help] of others" (Bava Basra 110a).

Eve was the reason that death came into our world, as we know. Vayikra Rabbah 20,2 on Psalms 75,5 states: "I said to wanton men: 'do not be wanton.'" Elisheva, daughter of Aminadav, did not rejoice in spite of five joyous events on the same day: The appointment of her husband as High Priest, the appointment of her brother-in-law Moses as king, her brother Nachshon as prince, her sons Eleazar and Itamar as deputy High Priests, and her nephew's Pinchas elevation to the priesthood. In spite of all this, her sons Nadav and Avihu entered the Sanctuary with אש זרה resulting in their death and turning her joy into mourning. This is why David warns us in the Psalm not to indulge in excessive joys. It is not given to the righteous to experience so much joy in this life. The Midrash mentions that G–d does not rejoice anymore in this world since He had to withdraw His שכינה due to Eve's sin but will rejoice only in the World to Come as we know from ישמח ה' במעשיו, that "G–d will once again rejoice in His accomplishments" (Psalms 104,31) [as He did when He completed the universe. Ed.]. In this world only the wicked experience true joy. There are several difficulties in this Midrash. Why does the author speak about Elisheva's having seen five joyous events on that day instead of the same joyous events "seen" by her husband Aaron? Did not her husband experience even greater joy on that day when he personally was elevated to the position of High Priest? He saw his brother crowned as king, his sons installed as deserving children, as mentioned in the Torah by the words למשפחותם לבית אבותם, "belonging to their families because they are descended from the house of their respective fathers," meaning that his sons are compared to him even more than to their mother? His sons became his deputies which demonstrated how closely they resembled their father in character traits. Some people want to answer our question by referring to the Talmud in Avodah Zarah 31 which regards the wife of a חבר, a pious person, as being equal to her husband. This means that she experienced that her sons regarded themselves as related to their mother as intimately as to their father. This is in line with the advice of our sages (Baba Batra 110a) who counsel a person to examine the brothers of a prospective bride to see what character traits he may expect to find in his bride. When the Torah reports the marriage of Aaron to Elisheva in Exodus 6,23, it stresses that Elisheva was Nachshon's sister. This proves that he was influenced by the character qualities of Nachshon. Still, I regard this answer as somewhat forced.