The Bible seems to indicate God threatened to kill Moses, but why?
Moses the Murderer
When Israel began to grow so large in population that Pharaoh began to wonder if they would overthrow Egypt during a war, Pharaoh ordered that all male babies be killed (Ex 1:9-17). Most of the Egyptian midwives refused to obey his command, and so Moses’ life was sparred as he was put in basket and sent down the river. It was only because of God’s providence that Pharaoh’s daughter took the child as her own. Even though Moses was raised by Pharaoh’s daughter, he was really raised by her servant, Moses’ mother, who was now also in the Pharaoh’s court. In the sovereignty of God, God made sure Moses had a good upbringing in education but also in where he and his family came from. Being in such a position as Moses was, he likely had the best education in the world, but Moses must have also heard about his own Israelite family roots through the accounts of Abraham , Isaac, and Jacob, but it is very likely that he was educated in geometry, science, mathematics, history, geography, architecture, and several other disciplines, and that learning would be valuable in surviving and traveling in the wilderness, but also in building the temple to exact specifications. Moses was poised to be the next Pharaoh of Egypt; the supreme leader of the greatest nation on earth at the time…until one day, perhaps sensing his own heritage, everything changed.
Moses rise and fall and later, rise again began “One day, when Moses had grown up, he went out to his people and looked on their burdens, and he saw an Egyptian beating a Hebrew, one of his people. He looked this way and that, and seeing no one, he struck down the Egyptian and hid him in the sand” (Ex 2:11-12). For one thing, Moses realized that he was not Egyptian but a Hebrew. But Moses apparently thought he had buried the body in the sand, but when Moses tries to break up an argument of his fellow brothers, they told him, “Who made you a prince and a judge over us? Do you mean to kill me as you killed the Egyptian?” Then Moses was afraid, and thought, “Surely the thing is known” (Ex 12:14-15), so “When Pharaoh heard of it, he sought to kill Moses. But Moses fled from Pharaoh and stayed in the land of Midian. And he sat down by a well” (Ex 2:16). Perhaps Pharaoh thought that Moses was a threat to a possible slave uprising, but ironically, he would be in on one, but it wouldn’t be from him but from God Who would deliver the nation.
Meanwhile, “the king of Egypt died, and the people of Israel groaned because of their slavery and cried out for help. Their cry for rescue from slavery came up to God. And God heard their groaning, and God remembered his covenant with Abraham, with Isaac, and with Jacob. God saw the people of Israel—and God knew” (Ex 2:23-25). That’s when God met Moses; first, in the burning bush, where God told him, “I have surely seen the affliction of my people who are in Egypt and have heard their cry because of their taskmasters. I know their sufferings” (Ex 3:7), so He told Moses, “I will send you to Pharaoh that you may bring my people, the children of Israel, out of Egypt” (Ex 3:10). As we know, it was by the strong arm of the Lord that He delivered Israel; God’s first born, even by taking the first born of every man and beast in Egypt to do it, at least for those who didn’t have the blood of the lamb on the door posts and lintels.
Did God Want to Kill Moses?
Now, when we come to a passage of Scripture, it’s best to look at the entire context, and where the Bible says that God threatened to kill Moses, we have to look at everything else around it. God had chosen Moses as His earthly representative to lead the nation of Israel out of their Egyptian bondage, but more than that, and I think more importantly than that, is God wanted Moses to instruct the people about His law and the critical priority that they must take in obeying it. God spoke to Moses, “Thus says the Lord, Israel is my firstborn son, and I say to you, ‘Let my son go that he may serve me. If you refuse to let him go, behold, I will kill your firstborn son’” (Ex 4:22-23), and in fact, that’s what happened. The first born of Pharaoh and all others who didn’t have the blood posted outside their door, all died. No one was exempt from this; Egyptian or Hebrew, so in this context, it says “At a lodging place on the way the Lord met him and sought to put him to death. Then Zipporah took a flint and cut off her son’s foreskin and touched Moses’ feet with it and said, “Surely you are a bridegroom of blood to me!” So he let him alone. It was then that she said, “A bridegroom of blood,” because of the circumcision” (Ex 4:24-26). First of all, it was the Lord Who was waiting to kill Moses but Moses’s wife, Zipporah , apparently knew that her son had to be circumcised, so she throws her son’s foreskin at Moses’ feet in anger. The Midianites did not practice circumcision. In fact, they detested it, and so when Moses didn’t even have his own son circumcised, and remember he knew better because God commanded it in Scripture, Moses was being disobedient, and at best, neglectful of the law of God. He broke the covenant which was intended to separate them as a people for Himself. By neglecting the circumcision of his son on the eighth day, Moses was not even being the head of his own household because Zipporah took the initiative and was angry that she was the one that had to do it and that Moses neglected to do what he was supposed to do. Zipporah’s actions appear to have saved Moses’ life because after she tossed the foreskin on the ground, it says of God, “he let him alone” (Ex 4:26a). Clearly the “him” in this context was Moses. God let Moses alone (or live) because of Zipporah’s actions.
Perhaps God wants us to learn that a spiritual leader must have his own house in order or he is not fit to serve as a leader. God’s anger would only be kindled against a leader who lives a life of disobedience, and one would even wonder, is that man really saved…or is he just deceived? God will not be mocked. Living a life of duplicity is not pleasing to God any more than it was with the religious leaders of Jesus’ day. It is as Isaiah the Prophet wrote (Isaiah 29:13), and whom Jesus quoted, “This people honors me with their lips, but their heart is far from me” (Matt 15:8), because, “to obey is better than sacrifice, and to listen than the fat of rams” (1st Sam 15:22).
Read more here: Moses From the Bible 
Resource – Scripture quotations are from The Holy Bible, English Standard Version® (ESV®), Crossway Bibles. (2007). ESV: Study Bible : English standard version. Wheaton, Ill: Crossway Bibles. Used by permission. All rights reserved.