It was not the Word of God from the O.T. that was abandoned. Not at all whatsoever. But the "natural men" of Israel's understandings of the law that were abandoned.
Jesus Himself, taught AFTER His Own Resurrection, from the O.T.
Luke 24:27
And
beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself.
It is this that the natural of Israel, were blinded to. They did not recognize 'God With them.' The Word, made flesh. The Word, Resurrected. The Spirit of The Word, sent into our own hearts by faith in Him.
Do you see pork, shellfish and animal killing in the law, or do you see JESUS?
I see Jesus by Every Word of God.
John 5:39
Search
the scriptures; for in them ye think ye have eternal life: and they are they which
testify of me.
We find Christ Himself being testified by the scriptures. All those Words of God, are in fact Him, Christ, Speaking.
Paul was turned from the power of Satan, of darkness, after Christs resurrection, by Direct Revelation. Acts 26:18.
The reality however is that "all of Israel" are Gods children to start with. Deut. 14:1, Psalm 82:6, Matt. 23:9. The real question is "why" can't they see Jesus or themselves? And these reasons, scriptures tell us, that THEY were blinded for US to receive Gods Mercy in Christ. Be thankful. Do not condemn them. Do not think God deals any differently with them, than with us.
Romans 11:
25 For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that
blindness in part is
happened to Israel, until the fulness of
the Gentiles be come in.
Gods Final Intentions are only to One, His Christ, His Body.
Eph. 2:
12 That
at that time ye were without Christ, being aliens
from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world:
13 But
now in Christ Jesus ye who sometimes were far off
are made nigh by the blood of Christ.
14 For
he is our peace, who hath
made both one, and hath broken down the middle wall of partition between us;
What two were made one? Israel and Gentile, in Christ.