John - "Is not the elect the Children of Abraham?"
Ping - The 144,000 referred to in Rev.14:1&3 and 7:4 are the tribes of "the children of Israel". Abraham had many children, including Ishmael and his descendants but (Gen.21:12) "through Isaac shall thy seed be called."
So the question is, who are the children of Israel and where are they today. We can't confuse the Israel here with the nation of Israel today, as it wasn't founded until 1948. There are 12 tribes, one of which is Judah - They are called Jews. Where are the other tribes?
John - "Being chosen by God predestinated to be conformed
to His image is this not like the predestination of Christ?"
Ping - It means the elect are already justified and predestined - they have a destiny and will fulfill it.
John - "Behold the Lamb slain from the foundation of the world?"
Ping - I don't understand your question. Please let me know what you mean.
So the idea that born again believers are only the elect of God is not good hermeneutics.
If all things are created in Christ and through Christ the all men were in Christ before the foundation of the world so all men were and are predestined for the opportunity of the new birth.
I am not say that all men will be saved but all men have the invitation to be saved.
Otherwise you have a God that is not the God of the Old and New Covenants.