Hello, Homer,
Thank you for your response.
I was going to comment, but I'm wondering what it means to you to "fulfill" and "obey" the law?
I myself do not use the language of "fulfilling" the Law. In the wake of Christian tradition, it has too great a potential for abuse. But with an eye to the Greek diction, to "fulfill" has more than one potential connotation, each drawing from the root sense of filling something up. This sense can be extended to mean accomplishing/carrying out some expectation or obligation. Thus, in the best sense, if I fulfill a command or a request, I have performed it in accordance with its intent (cf. Galatians 6:2).
If the command or request is an incidental one (e.g., "Drive me to the park next Tuesday"), then accomplishing it means that it holds no further claim upon the person who has accomplished it; if the command or request is a standing one (e.g., "Do not park on my lawn"), then its carrying-out is an ongoing matter, and it continues to hold claim upon the performer (insofar as the performer is able to meet the claim).
In the gospel of Matthew, the author generally uses "fulfill" (Greek:
pleroo) in a different way, as some manner of prophetic prediction being accomplished or some manner of typological pattern being pointed out. However, such usages are parenthetical by the narrator; when Jesus himself uses
pleroo, he never uses it in the formula which the narrator consistently employs for prediction or typology. Accordingly, when Jesus speaks of "fulfilling," there is a broader potential for interpretation than those two options (e.g., Matthew 3:15, 5:17, 23:32).
To obey means to conduct oneself in subjection to and in accordance with some locus of authority.
Such is my first stab at this. I'm not so good at definitions, however

, so I may need to revise/improve.
Shalom,
Emmet