When I seek the meaning of "Jacob" I understand it is what Israel was called before the transfiguration brought by God when He wrestled with him all the night through. I consider it (Jacob) to be the man of God in his incarnated human (born of Adam) nature.
Yes, exactly. He is Jacob before he becomes Israel. If you read Romans 9, 10, and 11, and try to get to the heart of what Paul is saying there, he is beating his breast about Jacob, his brothers the Jews, who are not yet the Israel of God because they have rejected the Messiah.
I say the truth in Christ, I lie not, my conscience also bearing me witness in the Holy Ghost,
2 That I have great heaviness and continual sorrow in my heart.
3 For I could wish that myself were accursed from Christ for my brethren, my kinsmen according to the flesh:
4 Who are Israelites; to whom pertaineth the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises;
5 Whose are the fathers, and of whom as concerning the flesh Christ came, who is over all, God blessed for ever. Amen.
But, we see by Romans 11, he is telling us, they have been blinded for a while so that the Gentiles can be brought into the family of God. After that, they will be grafted back into their own tree. And, so, all Israel will be saved. This is an end time prophecy Paul is making here. It is in the time of Jacob's trouble that they are grafted back in [in my opinion] because the Way is tribulation ['narrow']
23 And they also, if they abide not still in unbelief, shall be grafted in: for God is able to graft them in again.
24 For if thou wert cut out of the olive tree which is wild by nature, and wert grafted contrary to nature into a good olive tree: how much more shall these, which be the natural branches, be grafted into their own olive tree?
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.
26 And so all Israel shall be saved: as it is written, There shall come out of Sion the Deliverer, and shall turn away ungodliness from Jacob:
27 For this is my covenant unto them, when I shall take away their sins.
Verses 26 and 27 of Rom 11 is a direct reference to the prophecy made in the Old Testament about the house of Judah in the end times and how they will be brought into the New Covenant. Paul tells us the house of Judah will remain Jacob until they are grafted back in at the end of the age [when the fulness of the Gentiles has been achieved].
20 And the Redeemer shall come to Zion, and unto them that turn from transgression in Jacob, saith the Lord.
21 As for me, this is my covenant with them, saith the Lord; My spirit that is upon thee, and my words which I have put in thy mouth, shall not depart out of thy mouth, nor out of the mouth of thy seed, nor out of the mouth of thy seed's seed, saith the Lord, from henceforth and for ever.
-- Isa 595 To them belong the patriarchs, and from their race, according to the flesh, is the Christ, who is God over all, blessed forever. Amen.
28 As concerning the gospel, they are enemies for your sakes: but as touching the election, they are beloved for the father's sakes.
It's all about covenant, covenant, covenant.