Wherefore remember, that once ye, the Gentiles in the flesh, who are called Uncircumcision by that which is called Circumcision, in the flesh, made by hands;
What is not made by hands? Except for the Universe that was caused to exist by the Lord Himself, all else in the world is made by hands.
that ye were at that time separate from Christ, alienated from the commonwealth of Israel, and strangers from the covenants of the promise, having no hope and without God in the world.
Jesus himself made us quite sure about that when he forbade his disciples to take the gospel of salvation to the Gentiles. Have you ever read about that in Matthew 10:5,6?
But now in Christ Jesus ye that were far off are made nigh in the blood of Christ. For he is our peace, who made both one, and broke down the middle wall of partition, having abolished in his flesh the enmity, even the law of commandments contained in ordinances; that he might create in himself of the two one new man, so making peace; and might reconcile them both in one body unto God through the cross, having slain the enmity thereby.
The blood of Jesus had nothing to do with approaching man to God. What approaches man to God is repentance and obedience to God's Law. (Isaiah 1:18,19) Regarding the wall of partition, Jesus broke nothing; he rather added a few more bricks unto it when he forbade to take his gospel to the Gentiles. (Mat. 10:5,6)
God made certain covenantal promises to the Jewish people. In verse 12, the word covenants is plural because he is dealing with the four unconditional, eternal covenants God has made with the Jewish people: the Abrahamic Covenant, the Land Covenant, the Davidic Covenant, and the New Covenant. God's blessings are mediated by these four covenants. He also points out that God made a fifth covenant with the Jewish people, but unlike the other four, the Mosaic Covenant, which contains the Mosaic Law, was conditional and temporary. Among the purposes of the Mosaic Law, the purpose he deals with here was to serve as the middle wall of partition to keep Gentiles as Gentiles away from enjoying the spiritual blessings of the Jewish covenants.
All covenants established between God and men were and still are conditional to obedience of the Law. Nothing can be unconditional between God and man because of the attribute of Freewill. Man must agree with the terms of any covenant. The Jews agree; the Gentiles don't.
As long as the Mosaic Law was in force, if a Gentile wished to partake of the covenantal promises and blessings, he would have to undergo conversion to Mosaic Judaism, be circumcised, take upon himself the obligations of the Law, and live like a Jew had to live under the Law. So Gentiles as proselytes to Mosaic Judaism could benefit, but not Gentiles as Gentiles.
The "Mosaic" Law is still in force. Many times throughout the Tanach reference is made to the Decalogue as being God's Law and Mosaic Law without distinction between them. If one must insist for a distinction, it is found in the fact that the Mosaic Law includes the rituals. Jesus himself spoke of God's Law and the Mosaic Law without distinction when he said to listen to "Moses" aka the Law. (Luke 16:29-31)
Among the accomplishments of the death of the Messiah is that this middle wall of partition…the law of commandments was broken down. As Paul states it elsewhere, “the Law was rendered inoperative.”
According to whom, Paul? That's Replacement Theology. Besides, the Messiah is not supposed to die but to remain as a People before the Lord forever. (Jeremiah 31:35-37)