Our parashah opens with the account of Yisro’s arrival in the wilderness and his joining the people of Israel (18:2): ‘ויקח יתרו את צפורה אשת משה אחר שלוחיה ואת שני בניה... ויבוא יתרו חותן משה ובניו ואשתו אל משה אל המדבר,’ - “And Yisro took Tziporah the wife of Moshe, after her being sent away, and her two sons... and Yisro, the father-in-law of Moshe, came with his sons and his wife to Moshe, to the wilderness.” When we reach this posuk, a difficulty arises, for in Parashas Shemos we learned that when Hashem commanded Moshe to return to Egypt, it is stated (4:20): ‘ויקח משה את אשתו ואת בניו וירכיבם על החמור וישב ארצה מצרים’ - “And Moshe took his wife and his sons and mounted them on the donkey and returned to the land of Egypt.” If so, how did his family suddenly arrive in Midian, and now they are coming together with Yisro?
Rashi explains: “When HaKadosh Baruch Hu said to him in Midian, ‘Go, return to Egypt,’ ‘and he took his wife and his sons, etc.,’ Aharon went out to meet him and encountered him at the mountain of G-d. He said to him: Who are these? He said to him: This is my wife whom I married in Midian, and these are my sons. He said to him: And where are you taking them? He said to him: To Egypt. He said to him: Over the first ones we are distressed, and you come to add to them? He said to her: Go to your father’s house. She took her two sons and went.”
At a simple glance, one might think that Aharon and Moshe were speaking with one another about the security situation of the people of Israel in Egypt, who were then under the harshness of the bondage, and that Aharon was telling Moshe that it was not worthwhile to add more children of Israel who would be enslaved in Egypt. But this is not the truth, especially since the tribe of Levi was not subject to the bondage. Rather, Aharon was speaking about the spirituality of the people of Israel, who were then within the forty-nine gates of impurity. Concerning this he said to Moshe, “Over the first ones we are distressed, and you come to add to them.” How can you bring your sons into a place of spiritual danger? Moshe Rabbeinu accepted his words and sent them back to Midian.
Every father has a responsibility to guard his sons so that they distance themselves from any spiritual danger. This is especially so if he is engaged in communal needs or in bringing those who are distant closer; he must be careful that this not come at the expense of the spirituality of his sons. For Moshe Rabbeinu sent his sons so that they would not come to Egypt, and they did not see the ten plagues, and they were not present at the splitting of the Sea. Yet Chazal say (Mechilta Shira 3), “A maidservant at the sea saw what Yechezkel ben Buzi did not see.” Moshe Rabbeinu preferred that his sons forgo this, as long as he would not bring them into spiritual danger.
Based on a sichah in Kollel Shivti