Hi
Let me tell my understanding....
Noah...
Was close to God, but was selfish and did not teach God's ways because he felt most were unworthy of God's knowledge! There is not much we know from the time frame of Noah to Abraham. True we do know most of the ancestry because the Bible, Qu'ran and other books tell us more or less the same story!
Abraham...
Being much different than Noah, Abraham feared God, not in the way you might think. Abraham felt that the stories that were handed down to him lacked something, and that was a persons personal commitment to God was really non-existing. So Abraham wanted to make God the center of all things, this was something that had not taken place since the time of Noah.
Abraham first showed others his commitment to God, these things he did became laws not out the need to police others but because people saw that God granted Abraham great knowledge because of the things he did for God. One law was that everything you consumed was to be shared with God. Sacrifice and burnt offerings were other laws!
Many other direct descendents of Noah were not very happy with the fact that people were following Abraham laws and not obeying the laws Noah had passed on to his descendents! This was not the real problem though. What turned out to be the problem was the fact that some people took Abraham laws to far! Some loved God so much that they would offer there first born to God as a sacrifice! God do not want this, so he showed Abraham through his failure of falling a sleep while preparing his offering to God.
When he woke God told him, because you fell a sleep the offering you were to give me was taken, because of this you have showed me you do not care for me like I thought you did. So God ordered him to offer his son as a sacrifice! This was only to show Abraham that God did not like the fact that others were offering their first born children to him!
After this happen Abraham went to the people and told them they must never offer any child to God again. Many rebelled and said that Abraham only said this because he was jealous that God would grant them better favor than him.
This seems to be where the split happen, and we can tell why we know this because, many religions base there roots on these events!
Example.....
Judaism, Christianity, Islam, ( Voodoo -> a blend of Judaism, Christianity, Islam and African <- (Ham's desendents) pagan religions)
Although Christianity, was not formed then, it principles were based on Noahs beliefs...
Christianity differs from Islam and Judaism, because biblical beliefs....
Let me explain....
Jesus, in christianity is devine <- (of heaven), while in Islam and Judaism, Jesus is a prophet but is less than Abraham and while Abraham and Moses are devine, Jesus is not! There are many things that join all of these and other religions together in fact many other religions in some form or another base there foundation on Abrahams laws. (Baha'i, Rastafarianism, Unitarian Universalism)...
jtb!