Having abolished in his flesh the enmity, even the law of commandments contained in ordinances; for to make in himself of twain one new man, so making peace; Eph 2:15
Paul is not talking about Ten Commandments here because doing so will be contradicting his own statement in Rom 3:31 Do we then make void the law through faith? God forbid: yea, we establish the law. The same Greek word καταργέω is translated as void in rom 3:31 and abolished in Eph 2:15. In rom 3:31 Paul writes that we don’t make the law void but we Establish it.
Also See Circumcision is nothing, and uncircumcision is nothing, but the keeping of the commandments of God. 1 cor 7 : 19. Paul makes a line of distinction between the law of Moses and Commandments of God here. He says keeping of the commandments of does matters.
In Rom 7: 22 He says that ” For I delight in the law of God after the inward man: “, verse 25 he say “So then with the mind I myself serve the law of God;” So Paul always served the Law of God.
But in Eph 2:15 He is speaking about the law of commandments contained in ordinances. The greek word used here as ordinances is δόγμα which means the ceremonies. Also see the word occurs only one more time in New testament. It is in Col 2:14 Blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross; The ordinances here are the ceremonies (Drink offering, meat offering, Festival Sabbath) which were type to the ministry of Christ see Col 2:17 Which are a shadow of things to come; but the body is of Christ.
To know more on this see http://www.colossians-2-16.com/