Eph 2:16 says the middle wall of partition between Jews and Gentiles was broken down “by the cross”, not “at the cross”. There is a difference. Jesus provided the means of removing the middle wall of partition at Calvary, but the time that middle wall was removed was “in one body” (Eph 2:16), the church, and the church was not established until Pentecost (Acts 2:47), and middle wall was not pratically removed until God accepted the Gentiles into the church beginning with the household of Corenlius.
What God has done with the middle wall of partition is to make both Jew and Gentile members of the one body (I Cor 12:13), where all the members are united in purpose and work. He accomplishes the destruction of the wall by translating both Jew and Gentile out of the power of darkness (Rom 3:23) into the kingdom of the Son of His love (Col 1:13). In the Kingdom of Heaven, we have a NEW law, but it is attached to the old covenant of Abraham and is the one reward that God has always had for the faithful, and it has incorporated the same moral code–the 9 commandments–that are found in all three of God’s laws. The hope of Christians is identical to the hope of the Jews and the old Gentiles who still remembered God (e.g. Noah, Melchizedek, Adam, etc.).
The Law in its entirety still exists and still applies to Jews. It does not and never has applied to Gentiles (Dt 4:8, 5:3). Nothing of the Law has passed away. It simply is no longer the means of the Jew’s salvation. Christ is the means, and He wants Jews to become Christians and to become citizens of the Kingdom of Heaven where they will be in the one body (Acts 2:38). It is “in the body” that the middle wall is destroyed, and nowhere else. The means for enabling the kingdom (where “the body” is) and the consequent removal of the partition was the cross. Jesus paid in full and then removed our certificate of indebtedness at the cross (Col 2:14). He provided the means whereby every man could be translated out of the power of darkness into the kingdom where HIS law applies. The complete old law (either Moses or the Gentile Law, as appropriate) is thereby abolished for His citizens and His alone when they become citizens of the Kingdom of Heaven. The Law in its entirety still applies to all Jews that are not Christians. In this way you have both the Law in existence in every aspect until heaven and earth pass, but at the same time you have the middle wall of partition that is part of the Law that is broken down when Jews and Gentiles become members of the one body, become citizens of the kingdom, and become subject to the Law of Christ.