The commands to obey are simply to demonstrate that what you thought was possible (obedience) is not.
That answers the question, but how is it different from my guess at your answer in 347-349, namely that "the ethical teachings of the Scripture are there solely in order to prove to us our total depravity"?
Obviously, I think that answer is not satisfying, but before we discuss further I need to understand the answer in full.
When you claim that a “requirement” is given to compel a man obey on his own, you are making a Pelagian argument. Therein lies the connection.
“Requirements for holiness” are one thing. “Encouragements” for believers are another. Here hermeneutics comes into play. You say that a lot of weight is placed upon what Jesus said. We disagree.
Hermeneutically, you imply Jesus was here to teach “Christian living.” We fully, vigorously disagree. Here, again, our perspectives are miles apart. We understand that most of what Jesus was teaching during that “three year ministry” was to inform the Jews about the Law of Moses. The so-called Sermon on the Mount was a direct example of this claim.
In that Sermon, Jesus is saying, “You have heard (that the Law) said, ‘Thou shalt not kill’, but I say to you any man who calls his brother a ‘fool’ is worthy of Hell.” He was not teaching them “a better way”. He was driving them to say, “This crap cannot be done. It is impossible!” Much like the rich young ruler, when He told him to sell everything, give it all to the poor and follow Him. The man went away and Jesus says it is easier for a camel to go through the eye of a needle, than a rich man to enter heaven. Impossible. The disciples said, “Well then, who can be saved?” “What is impossible with man is possible with God.” What they could not do for themselves, He could (and would) do.
This represents a great difference in viewpoint. What we notice is that most of you Catholic folks don’t do what it is you claim He is teaching. For example, you don’t tear out your eye or cut off your hands when they offend. You go to confession. Hmmmm. Even though these are direct orders. And, you don’t always forgive folks, even though you claim that you cannot be forgiven unless you forgive (Matt. 6:15).
We don’t even attempt to obey these “requirements” because we know that He was teaching them the tough strictures of the Law and demonstrating their depravity. And, on top of that, the audience is the Jews (read Matt. 15 and the Canaanite woman). We Gentiles are not grafted in until the blood is shed and the enmity (the Law) is abolished, Eph. 2.
In the NT epistles, you begin to see the “encouragements” for us Gentile Christians to follow. These are quite different from the “requirements for holiness” needed under the Law. Notice the grappling in Act 15. The encouragements stop some of the death we spread (due to our brokenness) and guide our thinking about what God may be accomplishing in us. We are to strive together with Him. BUT, even that effort, interest and willingness is a gift placed in our lives along with the ability to accomplish any of these good things. It is not self-induced.
Is this any “fuller”?