I have met many Western Christians who are also uneasy about this story. I think both are mistaken. They are attempting to interpret the text through their own cultural filters and failing to see it through the eyes of those about whom and to whom it was written.
We know that human sacrifice was widespread in the centuries before and soon after the Old Testament period.
- In the ancient Near East the God Molech is described by many authors as consuming living babies.
- Chemosh in Moab required the occasional human sacrifice.
- The tomb of Queen Pur-Abi in Ur (the city from which Abraham had come) contained the remains of 5 soldiers and 23 ladies in waiting.
- It is believed by some that Phoenicians and Carthaginians sacrificed children.
- In the Americas, the Aztec, the Maya and the Inca almost certainly practiced human sacrifice.
- There is evidence for it amongst the Celts and the Vikings,
- and in India and China.
Now imagine the story of Abraham, not being read by an academic living at a time when human sacrifice has been outlawed for millenia, but being heard around the campfire by people to whom human sacrifice was the norm. To them, the really shocking thing about the story would not have been that Yahweh said "do it" (that is what gods did in those days) but that Yahweh subsequently said "stop".
And people, particularly people who do not have access to books, learn through stories. To a peasant who has grown up with human sacrifice, this is a story with an unforgettable punch line: a story worth a thousand finger-wagging admonishments. Here is a God on the point of getting the ultimate sacrifice from one of his followers saying "stop - I don't want it"
It is arguable that this story of Abraham and Isaac has actually been redundant for the last thousand years, having done the job God intended for it. The three Abrahamic religions have wiped human sacrifice, once so common, from the face of the earth. It is banned in every country on the planet and has almost completely disappeared from every culture. We cannot wind back and re-run history without Abraham, but it is a fair guess that this story which Dawkins so derides has played a part in that triumph.