When a woman enters into a marriage covenant with a man she takes on his family name. Not his first name but his family name. Demonstrating by name that she belongs to him. The children born through this covenant also bear their Father's family name.

Ephesians 3:15
Of whom the whole family in heaven and earth is named,

Romans 7:3,4
So then, if she (the Jews) marries another man while her husband (YHWH) is still alive, she is called an adulteress. But if her husband dies, she is released from that law and is not an adulteress, even though she marries another man.(Yahshua/Jesus) So, my brothers, you also died to the law through the body of Christ, that you might (marry) belong to another, to Him who was raised from the dead, in order that we might bear fruit to God.

Judaism was a covenant marriage with God. That is why the Jews were punished for straying from Judaism which was adultery. Until; Jesus came in the name of the new eternal covenant and by His death put an end to all other covenants. Since Jesus Christ is the Husband that the Spirit of Truth is referring to, it makes sense that those to whom He has entered into the new covenant with would be named Christians.

Philippians 3:5-9
circumcised on the eighth day, of the people of Israel, of the tribe of Benjamin, a Hebrew of Hebrews; in regard to the law, a Pharisee; as for zeal, persecuting the church; as for legalistic righteousness,faultless. But whatever was to my profit I now consider loss for the sake of Christ. What is more, I consider everything a loss compared to the surpassing greatness of knowing Christ Jesus my Lord, for whose sake I have lost all things. I consider them rubbish, that I may gain Christ and be found in him, not having a righteousness of my own that comes from the law, but that which is through faith in Christ--the righteousness that comes from God and is by faith.

Paul was Jewish born and raised as evidenced in his treatment of the Christian faith. Jesus Christ revealed himself, to Paul, and he became a Christian by his Faith in Jesus. Considering Judaism, of no value, compared to his eternal relationship with God through the covenant of Jesus.

Judaism has come to an end by the death of Jesus Christ. Jesus resurrection from the dead allows all people to enter into a new covenant with God. Same God, new name, new covenant. The apostles and prophets of Christ were all Jews. The books of the Holy Scriptures, which proclaim Jesus, were delivered to the world through men who were born and raised Jews.

This new covenant opened the door of eternity to the Gentiles. By this He has declared His love for all people, especially the Jews. The only thing that has changed is, the covenant, not His love.

Romans 11:11
I say then, did they stumble (the Jews) that they might fall? God forbid: but by their fall salvation is come unto the Gentiles, to provoke them (the Jews) to jealousy.

Romans 11:11 declares Gods love for all peoples to be drawn to His new covenant as one people under one Name. Provoking the Jews to the new covenant, by the gentiles.

Ephesians 2:16-18
and in this one body to reconcile both of them to God through the cross, by which he put to death their hostility. He came and preached peace to you who were far away and peace to those who were near. For through him we both have access to the Father by one Spirit.

True Christianity excludes no one and reaches out to everyone. Just because someone refuses Jesus today does not exclude them from receiving Him tomorrow. Pauls life is an example of this and recorded for us to learn from.

Romans 11:30-32
Just as you (Gentiles) who were at one time disobedient to God have now received mercy as a result of their disobedience, so they (Jews) too have now become disobedient in order that they too may now receive mercy as a result of God's mercy to you. For God has bound all men over to disobedience so that He may have mercy on them all.

Acts 26:28
King Agrippa replied to Paul, "In a short time you will persuade me to become a Christian."

Luke 24:46,47
He told them, "This is what is written: The Christ will suffer and rise from the dead on the third day, and repentance and forgiveness of sins will be preached in His name to all nations, beginning at Jerusalem.

If we are not doing this, we are not true Christians. The old covenant has been replaced with one that is far better because it is offered to all peoples, Jews and Gentiles as one, in Jesus Christ.

Hebrews 10:9
then He said, " Behold, I have come to do your will." He takes away the first in order to establish the second.

Hebrews 8:13
By calling this covenant "new," He has made the first one obsolete; and what is obsolete and aging will soon disappear.

Hebrews 7:22
Because of this oath, Jesus has become the guarantee of a better covenant.

Hebrews 8:6
But the ministry Jesus has received is as superior to theirs as the covenant of which He is mediator is superior to the old one, and it is founded on better promises.