text: why was the lord about to kill moses? 24 at a lodging place on the way, the lord met {moses} and was about to kill him. 25 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. 26 so the lord let him alone. (at that time she said "bridegroom of blood," referring to circumcision.) (exodus 4:24-26) i love the amplified bible. it gives insight into things like this. the niv, which you are quoting, is not very accurate, by the way - use a parallel bible with several versions beside each other, and it'll help.  moses neglected to circumcise one of his sons because his wife (zipporah) was opposed to it. therefore, he was honoring the will of his wife above the command of god.  it was very important for moses to learn that god means what he says at this point, because he was going to be leading the nation of israel and representing god to them.