Exo 4:24 And it came to pass on the way, at the encampment, that the LORD met him and sought to kill him.
In Exodus 4 we read about the time that God was going to kill Moses. The passage actually just starts out by saying it. We only learn the reason (why God wanted to kill Moses) by extrapolation. It was about circumcision:
Exo 4:25 Then Zipporah took a sharp stone and cut off the foreskin of her son and cast it at Moses’ feet, and said, “Surely you are a husband of blood to me!”
Exo 4:26 So He let him go. Then she said, “You are a husband of blood!”—because of the circumcision.
God wants to kill Moses. Moses’ wife circumcises Moses’ son (something traumatizing for her to do). And then curses Moses. God proceeds to “let Moses go” (not kill him). God was angry that Moses was not circumcising his son. Moses seems to have been pressuring his wife to circumcise, but she was resisting. When in danger, she finally decided to go through with it, but then curses Moses and throws the foreskin at him!
This is all because God took seriously His requirement that all Jews be circumcised:
Gen 17:14 And the uncircumcised male child, who is not circumcised in the flesh of his foreskin, that person shall be cut off from his people; he has broken My covenant.”
The only long break in this practice was during the Exodus. But (painfully), that was remedied as soon as they reached the promised land:
Jos 5:3 So Joshua made flint knives for himself, and circumcised the sons of Israel at the hill of the foreskins.
Jos 5:4 And this is the reason why Joshua circumcised them: All the people who came out of Egypt who were males, all the men of war, had died in the wilderness on the way, after they had come out of Egypt.
Jos 5:5 For all the people who came out [of Egypt] had been circumcised, but all the people born in the wilderness, on the way as they came out of Egypt, had not been circumcised.
Joshua made a hill of foreskins… ick!