Regarding Torah and Tanak, when Jesus was asked about the resurrection, He had to find the proof only in Torah, because Saducees disbelieve the rest of Tanak other than Torah as a genuine part of Words of God. Saducees didn't approve Daniel ch 12 or Isaiah or Job as the genuine part of God's Word. Therefore whenever there was a debate between Pharisees and Saducees, it bacame the debate about the authenticity of the Prophets. Therefore Pharisees could never convince Saducees about the resurrection.
When Jesus came to the world, He knew the truth about the resurrection is stated in Torah also, even though Pharisees didn't know about it.
Pharisees were very much amazed because it was a question bothering them so much in the past.
If Jesus presented other part of Bible (Tanak) to convince Saducees, they would have rejected it, because Saducees disbelieve the other part of Tanak than Torah.
What Jesus pointed out is the tense, I believe.
Jesus mentioned that The present Tense was used for God of Abraham, God of Issac, God of Jacob. If they all died and didn't exist then current time, then the past tense should have been used.
Pointing out that amazed the people.
Of course, it is related to the fact that Abraham, Issac, Jacob are the people having Eternal Life, Living Men.
Pre-existence of Jesus is what I have been emphasizing all the time and that's why I fought against Mother of God concept in the other thread, vigorously.
Hope now everyone can return to the original subject.