you were dead and condemned by the law, but by faith you have died to the principles of the world, and to the law, being crucified with Christ so that you may live in Him with all your transgressions forgiven. don't let anyone deceive you with hollow philosophies of living according to the tradition of mankind; you are forgiven and under no condemnation, having a righteousness not by the Law, which condemned you, but apart from the Law. this is your spiritual circumcision, His crucifixion, yours in Him, and the curse of the Law is removed from you by it.
therefore
don't let anyone judge you because you rigorously keep the Law. but just part of it, no, not the part Jesus said is the crux of it, another part, the marriage covenant of God and the nation Israel. in fact, obviously, keep the Law, especially you must keep the ritual observance of days, because obviously, you are no longer under the curse of the Law, so, you have to..
considering what's before the "therefore" in v. 16 i just don't see how that interpretation should come after it.