"Moses went out to meet his father-in-law; he bowed low and kissed him; each asked after the other's welfare, and they went into the tent" Exodus 18:7
This family reunion embodies everything one might wish for in a relationship with one's in-laws: respect, affection, concern and companionship. Jethro was more than a family member; he was one of Moses's most trusted advisors. As we feel heart-warmed by this meeting, there is someone who is notably absent.
Jethro brought his daughter Zipporah and grandsons from Midian as part of this reunion. Moses was not only seeing his father-in-law after a prolonged absence; he was also reuniting with his wife and sons. But when Jethro announces his arrival, he tells Moses that he has come with "your wife and her two sons". They are his sons as well. Why is this not acknowledged and why does Moses take his father-in-law into his tent while his wife and sons appear to stand outside? They do not enjoy any of the attention and affection lavished between these two men in the biblical text.
The Zohar, an important medieval mystical commentary on the Torah, observes that these two sons are called her children because she raised them alone. Moses, engaged in the large landscape of national leadership, pays a price for his sacrifices. The sages of the Talmud acknowledged as much, as did Maimonides, who believed that Moses did not engage in the banalities and joys of raising a family because of his larger mission.
Leadership has costs. It is extremely hard to balance all of one's loves in one lifetime. For the moments that we stand outside Moses's tent with Zipporah and her sons, we understand that sometimes that price may be high indeed. This is the last time Zipporah will appear in a biblical narrative.