The near ritual murder involving Isaac:

In Genesis 22:1-18, God decided to test the depth of Abraham's faith. God ordered Abraham to travel to the top of a mountain in the land of Moriah, and there murder his own son, Isaac, as a human sacrifice. At the last minute, as Abraham was about to stab his son to death, an angel appeared and ordered Abraham to stop. A ram which was caught in a thicket was used as a substitute for Isaac. The passage assumes that God is not omniscient, because he did not know the depth of faith of Abraham without testing him in this way. The immorality of this story is the massive traumatic stress that both Isaac, his father, and mother experienced during this event. Compounding this is the willingness of a father to murder his own son. It is doubtful that either would have been able to be fully normal afterwards.

Mass murder of the first-born of Egypt:Exodus 7:3:"...I will harden Pharaoh's heart, and multiply my signs and my wonders in the land of Egypt."Exodus 7:13-14:"And he [God] hardened Pharaoh's heart, that he hearkened not unto them; as the LORD had said. And the LORD said unto Moses, Pharaoh's heart is hardened, he refuseth to let the people go."Exodus 12:29-30: "And it came to pass, that at midnight the LORD smote all the firstborn in the land of Egypt, from the firstborn of Pharaoh that sat on his throne unto the firstborn of the captive that was in the dungeon; and all the firstborn of cattle. And Pharaoh rose up in the night, he, and all his servants, and all the Egyptians; and there was a great cry in Egypt; for there was not a house where there was not one dead." God "hardened Pharaoh's heart" to prevent him from easily giving into the requests of Moses to release his people from slavery. Because God made the Egyptian ruler resistant to the idea of freeing the Israelites, the pharaoh ignored a variety of plagues. Finally, God killed the first born of all of the humans and cattle in Egypt, except for those of the Israelites who had ritually killed a male lamb and daubed its blood over the doorposts of their homes. The death toll must have been enormous, as every Pagan family was affected. Mass murder of children is inexcusable by today's moral standards.