Yes, Christ, Paul, James, etc....used the OT to prove that Christ was indeed the fortold Messiah. They also referred to incidents in the OT as WARNINGS and also incidents of faith. NEVER did they refer people to following the Mosaic Law codes rules and regs. In fact, the big to do in Acts was over the Jewish Christians intending to impose the circumcision on the Gentile Christians.
The big to do with the Jews charging Paul before his death had to do with his telling people they were no longer required to carry out the Mosaic Law.....'ya darn skippy he did.
If you want to live under ANY aspect of the Mosaic Law, than you have to live under ALL aspects of it....you're gonna need a whole lot of cattle for that.
Besides that, if you wanna impose the Code on others, than you have just made Christ's sacrafice meaningless. What you would be saying is that Christ died for NOTHING....and Jah wasted his time and Son on you.
"Furthermore, though YOU were dead in your trespasses and in the uncircumcised state of YOUR flesh, [God] made you alive together with him, he kindly forgave us all out trespasses and blotted out the handwritten document against us, which consisted of decrees and which was in opposition to us; and He has taken it out of the way by nailing it to the torture stake." -NWT Col. 2:13,14
Sure, the OT is a good reference in helping any Christian prove that Christ is the one the text points to as the Messiah. Its beneficial in to understanding what the heck is going on but it isn't meant for Christians to be under that code. It gives us a reference for absolute joy to know Jehovah has given Christians a much better arrangement.