The apostle Paul wrote in Ephesians 2:25 that Jesus Christ has abolished the law of commandments.

Eph 2:15  having abolished in His flesh the enmity, [that is,] the law of commandments [contained] in ordinances, so as to create in Himself one new man [from] the two, [thus] making peace,

At first sight it looks like Paul is saying that the Ten Commandments have been abolished.  But this cannot be the meaning as Jesus said that He did not come to destroy (abolish) the law, but to fulfill it.

Mat 5:17  “Do not think that I came to destroy the Law or the Prophets. I did not come to destroy but to fulfill.

What did Paul mean?  Let’s take a close look.

As always, it helps to look at the context. 

Eph 2:11  Therefore remember that you, once Gentiles in the flesh—who are called Uncircumcision by what is called the Circumcision made in the flesh by hands—
Eph 2:12  that at that time you 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.
Eph 2:13  But now in Christ Jesus you who once were far off have been brought near by the blood of Christ.

The church at Ephesus had mostly gentile converts in it, who prior to their conversion had no access to the promises of salvation that God had made known through Israel.  Paul mentions circumcision because that was a sign that the Israelites were His people.  It was decided by the apostles early on that circumcision was not required for Gentile converts.

Eph 2:14  For He Himself is our peace, who has made both one, and has broken down the middle wall of separation,

In Jesus Christ, Jew and Gentile are alike; they are one.  Paul wrote something very similar in Galatians 3:28.

Gal 3:28  There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus.

There was a great separation between Jew and Gentile, symbolised by this “middle wall of separation”.  But now, in Jesus Christ, Jew and Gentile are no longer separated, but one, thus breaking down “the wall” that separated them.  But what is this “middle wall of separation” that Jesus has broken down? 

At the time of both Jesus and Paul writing to the church at Ephesus, there was a temple in Jerusalem (known as Herod’s temple) where people came to worship God.  In the outer courtyard of the temple was a wall separating the Court of the Gentiles from the Court of Israel.  This wall kept Gentiles from entering the section of the temple that was for Jews only.  Crossing the wall carried the death penalty for any Gentile.  No command by God can be found in the Scriptures for this wall.  It appears to be entirely a Jewish construct.

The New International Commentary of the New Testament: The Book of Acts explains (1974, p. 434):

That no Gentile might unwittingly enter into the forbidden areas, notices in Greek and Latin were fixed to the barrier at the foot of the steps leading up to the inner precincts, warning them that death was the penalty for further ingress. Two of these notices (both in Greek) have been found—one in 1871 and one in 1935—the text of which runs:

‘No foreigner [gentile] may enter within the barricade which surrounds the temple and enclosure. Anyone who is caught doing so will have himself to blame for his ensuing death’.

This is the “middle wall of separation” Paul refers to in Eph 2:14.  The wall was a symbol of the separation between Jew and Gentile.  The Romans broke down this in A.D. 70 when they destroyed the temple.  Jesus Christ broke down the separation between Jew and Gentile that this wall represented.

Let’s continue, coming now to the verse in question.

Eph 2:15  having abolished in His flesh the enmity, [that is,] the law of commandments [contained] in ordinances, so as to create in Himself one new man [from] the two, [thus] making peace,
Eph 2:16  and that He might reconcile them both to God in one body through the cross, thereby putting to death the enmity.

Jesus, by His death, has brought Jews and Gentiles together, into one body, or one church, and destroyed the enmity between them.  The enmity between Jew and Gentile caused the separation.  The enmity is “the law of commandments contained in ordinances”, which is more clearly rendered “the rule of decrees contained in regulations (made by men)”.  God’s commandments (which show man how to love God and his neighbour) cannot cause separation.  It was the Jewish (man-made) rules and regulations that separated Jew from Gentile.  These rules and regulations included circumcision, ceremonial laws, the Jewish oral law, and traditions.  The Jewish (man-made) rules and regulations are symbolized by the “middle wall of separation.” 

We have seen that the “law of commandments” Jesus Christ abolished is the man-made Jewish rules and regulations which separated Jew from Gentile.