I’ve sometimes wondered the same thing. If God wants to kill someone, He can do it any time, anywhere, anyhow. Ananias and Sapphira dropped dead on the spot, in response to Peter’s declaration of the death penalty for lying (which I always thought was a bit tough). I notice though that Peter never did anything like it again. I don’t think he was happy about the outcome, bearing in mind his own failings some time earlier.
However this is part of the Jewish Scriptures, and so I went looking for Jewish commentary on the episode. I found a few explanations at the following link, and posted the simplest below.
hebrewroots.com/node/451
This is a very similar issue question to the previous one. “God sought to kill Moses” or did He? The incident certainly produced a response from the hitherto uncooperative Midianite daughter of Jethro, Zipporah! Like it or not she had married into God’s covenant people and circumcision! Who said Jewish identity only or even primarily comes through maternal descent? Forget Ephraim and Manasseh if so!
Is this from Rabbinical Halachic law or God’s Law? As with the previous question, the answer surely lies in another question, “Who has known the mind of the Lord?” (Romans 11:34 - check out the context and compare also with 1 Cor 2:16).
Bear in mind Moses married a couple of Midianite women who were not Jewish. They’d probably drawn the line at Moses’ demand that their infant sons should be circumcised, and Moses, after having looked after a bunch of sheep for forty years, his once princely confidence shattered, all washed up, not very eloquent, and now being told by a burning bush to go and confront Pharaoh.
That’s like a near broke 80 year old red neck, having been told off by a burning bush in the back yard, marching into the White House via the Pentagon, carrying a stick, and confronting the American President, who is backed up by the military industrial complex and more money than you can shake a stick at. Compared to that, what’s the big deal about a circumcision?
The last thing Moses wanted or needed at that point was a prolonged bout of nagging wife upset about her kid getting circumcised.
Notice it was Zipporah, one of his Midianite wives, who changed her mind, and circumcised her own son. Presumably she saw the writing on the wall, and realised the gravity of the situation.
Exodus 4:25 NIV
But Zipporah took a flint knife, cut off her son’s foreskin and touched Moses’ feet with it. “Surely you are a bridegroom of blood to me,” she said.
In other words, if God was going to make Moses the leader and founder of the Jewish nation, he needed to make a visible start by getting his own kids circumcised.