Indeed those who are in Christ, put another way---those who are disciples of Christ will do what He wants and will emulate what He did. Jesus Christ did tell his disciples to preach the Gospel and to go out and make disciples and baptize. In Luke 24 Jesus Christ is very specific on their primary mission:
Luke 24:
44 Then He said to them, “These are the words which I spoke to you while I was still with you, that all things must be fulfilled which were written in the Law of Moses and the Prophets and the Psalms concerning Me.” 45 And He opened their understanding, that they might comprehend the Scriptures.
46 Then He said to them, “Thus it is written, and thus it was necessary for the Christ to suffer and to rise from the dead the third day, 47 and that repentance and remission of sins should be preached in His name to all nations, beginning at Jerusalem. 48 And you are witnesses of these things. 49 Behold, I send the Promise of My Father upon you; but tarry in the city of Jerusalem until you are endued with power from on high.”
I think the above is very clear. Of the OT scriptures, the focus is what they have to say about Jesus Christ and finding Him; and most importantly the purpose of His death and resurrection. Not splitting hairs, but I fail to see the commission for teaching the Law.
To stay specifically within your proof texts, how does one preach 'repentance and remission of sins' (Lk 24:47) without transmitting the definition of sin? How does one define sin without Torah? Knowledge of sin is found therein. What else defines wickedness (twisting of Torah) and iniquity (lawlessness)? How does a pagan understand what he has done and why it warrants the grace that comes with Messiah? How does he understand how another can take his place? How can he know 'right living' after the fact of his salvation? How is that given to the next generation?