What is happening in the 'bloody husband' passage where God seeks to kill Moses?

The context helps, because this is early, in Exodus 4, just as God is about to send Moses to Pharaoh. Moses had spent forty years in Midian being humbled to become a leader, and there he married Zipporah, a Midianite, daughter of Jethro. What probably happened is this: Zipporah, being a Midianite, was not familiar with circumcision, which for the Jews was the sign of the covenant given in Genesis 17, done to the male on the eighth day. If the son here is the second son, Eliezer, then the boys are older, and Gershom may not have been circumcised either. Most likely Zipporah did not want Moses cutting the flesh off her son, and they had been arguing about it, a family dispute that went nowhere. So God confronts Moses, because if you cannot keep your own family in line you are not fit to lead Israel out of Egypt, just as Paul later says a man who wants to be a bishop must keep his own household in order. The word for what God sought to do is real; it means to kill, and there is no softer meaning. So, reading between the lines, God means business at this first meeting, and Zipporah, watching and knowing her husband's life is at stake, takes a sharp stone, cuts off the foreskin, and throws it at Moses' feet, saying he is a bloody husband to her, because to her this is disgusting, but it is flesh for life. After that it is over, and Moses is ready to take up his role as leader. It even carries symbolic meaning, since flesh was cut off so that there could be life, pointing to Christ.