Hey sister Hope, salam alaikum!
I came by this post by accident, and although, just as you, I'm aware of brother Joseph's views on this matter, and I admire and respect his works greatly, there are questions in my mind about this thing as well.
I noticed the Bible passages you quote. I've studied the Bible with evangelists and jehovah's witnesses, and I can tell you that there are details in that rise questions.
1) "Then God’s angel said (to Hagar): “I will greatly multiply your offspring, so that they will be too numerous to count." God’s angel added: “Here you are pregnant, and you will give birth to a son, and you must name him Ish′ma·el, for God has heard your affliction. He will be a wild donkey of a man. His hand will be against everyone, and everyone’s hand will be against him, and he will dwell opposite all his brothers.” (Genesis 16:7-12).
2) "Then she went on and sat down by herself, about the distance of a bowshot away, because she said: “I do not want to watch the boy die.” So she sat down at a distance and began to cry aloud and to weep. At that God heard the voice of the boy,+ and God’s angel called to Ha′gar from the heavens and said to her: “What is the matter with you, Ha′gar? Do not be afraid, for God has heard the voice of the boy there where he is. Get up, lift the boy and take hold of him with your hand, for I will make him a great nation.” Then God opened her eyes and she saw a well of water..." (Genesis 21:17-19)
So, this son of Abraham would be a wild man, a "wild donkey"like man, who would have his seed greatly multiplied, would be the father of 12 powerful rulers, but would have many enemies ("His hand will be against everyone, and everyone’s hand will be against him").
At the moment of sacrifice: “Do not harm the boy, and do not do anything at all to him, for now I do know that you are God-fearing because you have not withheld your son, your only one, from me.”(Genesis 22:12). (It would make sense to use ''the only son you're left with", but "the only son" means "the only son", which strongly suggests a second son is not born yet.). Furthermore:
“‘By myself I swear,’ declares God, ‘that because you have done this and you have not withheld your son, your only one, I will surely bless you and I will surely multiply your offspring like the stars of the heavens and like the grains of sand on the seashore, and your offspring will take possession of the gate of his enemies. And by means of your offspring all nations of the earth will obtain a blessing for themselves because you have listened to my voice." (Genesis 22:16-18)
God was so satisfied with this forbearing and obedient son, so that he promised he will take possession of the gate of his enemies. The thing is, if this boy is Isaac, how come God promises to make him victorious over his enemies, when God never foretold that Isaac will have any enemies, while regarding Ishmael he foretold the contrary? Plus, through him all the nations of the land would obtain blessings! All the prophets (and scripture) who came from Isaac's lineage were sent to their people and their period only, only Muhammad's message was meant to be a universal message for all mankind. Everything in the Bible seems to suggest Ishmael was the sacrificing son but the name seems to have been replaced intentionally, otherwise the circumstances described there don't fit.
As the Quran doesn't give us an exact name, it does tell us that when Abraham prayed for an offspring from the righteous, Allah didn't answer immediately, first He gave him a forbearing boy, and afterwards, a test. After Abraham passed the test of nearly sacrificing this forbearing boy (his "only son"who obeyed without objection), Allah rewarded him by answering the prayer he had made for the righteous son, Isaac
. Abraham fathered many tribes, but in the Quran he only thanks God for giving him Ishmael and Isaac. Because of the promises God made for these two in both Bible and Quran!
If prophet Muhammad didn't fulfill the prophecy of blessings that would come from the prophet Ishmael (assuming from both Bible and Quran that he is the sacrificed son), then this prophecy remains unfulfilled to this day.
I attach an interesting article about a DNA test which shows jewish and arabs have been united by genes for 4.000 years!
http://www.dangoor.com/73page25.htmlGod bless you all,
Selam.