There are obviously some major gaps in your theological grasp and reasoning.

For starters, God's fore-knowledge is not the issue. God may or may not chose to use his foreknowledge, just as he may or may not choose to use his power. For example, being Almighty does not mean that God uses his power at all times.

The issues centered on Abraham had to do with faith. Faith is something that has to be demonstrated by the individual. In the case of Abraham, God had already promised Abraham that the messiah would come through Isaac's linage. And even though Sara and Abraham doubted that God could give them a child in their old age Jehovah kept his promise and the barren woman became a mother.

But when the child had grown up God asked Abraham to sacrifice his son. So, on the one hand God had already made a sworn statement that the messianic seed would come through Isaac how would that be possible if Abraham obeyed God and sacrificed his son? It was a test of Abraham's faith to be sure. 2,000 years later the apostle Paul explained to the Hebrews that Abraham demonstrated faith in God's ability to resurrect the dead, and in an illustrative way Abraham received Isaac back from the dead, as Paul noted here [link to www.biblegateway.com]

Interestingly, Isaac is called Abraham's "only begotten son." In this we are reminded that Jesus is called "the only begotten Son of God." But contrary to the case of Abraham, Jehovah did not spare his precious son but sent him to earth to die a sacrificial death as the slaughtered lamb of God. It would seem then that the drama that was played out with the attempted sacrifice of Isaac was pictorial of how Jehovah would literally sacrifice his only begotten son on the figurative altar.

Because of Abraham's faith he is called the father of all those with faith, faith in the sacrificed son of God, that is.

Another interesting side note: Before Abraham attempted to offer up Isaac there is no record that the Canaanites, among whom Abraham was residing at the time, practiced ritual child sacrifice. It would seem then that the attempted sacrifice of Isaac was met with mockery by the demons, who undoubtedly understood the deeper meaning as regards the future sacrifice of Jehovah's own son, and so to mock and devalue that sacred sacrifice the demon gods who were worshipped by the Canaanites compelled their worshippers to institute the ritual sacrifice of their own children--a demonic ritual which the sons of Abraham eventually adopted as well.

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