Well, the Lord Jesus Christ said in the red letters to keep and observe all that the Pharisee commands because he sits in the seat of Moses. That is "New Testament", from God himself.
My point is, don't preach obedience unless you have a reason. Such as showing people fall short of obedience. And through one man's obedience, the gift of life came to all men.
Except if all we teach is that people fall short then does anyone obey what God and Jesus have commanded? If not, was it because we did not know what the commands were, was it because we were unable to do so, was it because though it is possible we chose not to, or was it that we just didn't listen and observe what we were instructed to do?
If God's commands are for our obedience, why do we think they are only to condemn the sinner showing him where he falls short and where he is unable to obey on his own? If we fall short on our own, does that mean that there is a way not to fall short? Meaning, before God we fall short. But with God can we succeed in obeying His commands? This is either by the Spirit or because obeying God is elementary and we somehow have taught ourselves into oblivion to think it is impossible. Because we have all fallen short of God's glory and because we know this from God's commands including the Law of Moses and other Old Testament commands and also what Jesus taught, we know that only in Jesus can we have salvation. But we are not saved in order to sin and be disobedient. We are saved in order that we would obey God and glorify Him, having been completely forgiven of our sins before God in Jesus Christ.