What does it mean "bi'Mekom asher Yishchatu es ha'Olah
What are the ramifications of "Chatas Hu"?
Rashi: It is Kosher only if it is brought Lishmah, but Pasul if it is brought Lo Lishmah.
Rashi writes that the angel wanted to kill Moshe for settling the lodging before circumcising. It would endanger the baby to circumcise him, for Moshe must go to Egypt tomorrow!
Hadar Zekenim (1): This was after Moshe had returned to Egypt, so there was no danger.
Da'as Zekenim, Hadar Zekenim (2), Moshav Zekenim (1): This was after Aharon convinced him not to bring his wife and children to Egypt. 1 Tziporah could stay with the baby until he is healed 2 and able to return to Midyan.
Riva (1), Moshav Zekenim (citing Mizrachi): The Malon was close to Egypt, so there was no danger to circumcise and go to Egypt.
Riva (2): Hashem did not command him to take his wife and children. Moshe should have circumcised him in Midyan and left him with Tziporah.
Moshav Zekenim: Milah on day eight overrides Shabbos. All the more so it overrides Hashem's command to go to Egypt! Moshe would not have erred about this. Rather, he neglected circumcising Gershom.
Da'as Zekenim, Hadar Zekenim: Even though Shevet Levi was not enslaved, he did not want his wife and children to see Yisrael in distress.
Moshav Zekenim: Moshe intended that Tziporah stay there until he takes Yisrael from Egypt, but she did not want to wait, and returned to Midyan. Alternatively, initially he left her there, and after he came to Egypt, he made a Shali'ach to tell her to return to Midyan, for he saw that it will be a long time, i.e. a month between Makos.