Anthony Garland wrote a 2003 paper in The Conservative Theological Journal entitled "Does Dispensationalism Teach Two Ways of Salvation?" Since Academia.edu recently recommended I read it, I issued him this challenge after downloading the paper:
Since I see no justification from the immediate context of Matthew 5:17-21 to presume the 'fulfillment' of the law meant anything other than the sinner's own fulfillment of it, it appears that Jesus really did teach legalism, which doubles as a reasonable hypothesis for why the Judaizers existed in the first place.
Since I see no justification from the immediate or larger context of Matthew 28:20 to justify delimiting the "all" in "all that I taught you", I am reasonable to believe that, at least for Matthew and his school, Gentiles don't become true disciples unless they obey all that Jesus taught according to that particular gospel. And yet you'd have to search long and hard for any American Christian today who seriously obeyed "all" that Jesus taught the disciples in that gospel.
Since biblical inerrancy is denied by most Christian scholars, and since those who espouse it disagree with each other about its nature and scope, this is an objective justification for refusing to view that doctrine as a governing hermeneutic. it is far more controversial than other heremenutical rules like grammar, context, genre, etc. In short, reading Matthew's legalistic Jesus through the rose-colored glasses of Ephesians 2:8-10 is an absurdly subjective preference and does precisely ntohing to intellectually compel the non-Christian reader to think that the only correct interpretation of Jesus is the one that harmonizes with apostle Paul's opinions.
If you want to find a lot of dispensationalists who insist that Jesus' pre-cross teachings no longer apply to the modern church, take a look at evangelical Protestantism of the last 100 years. Jesus is the ultimate authority on how to get saved, and he said plenty about it...but today's Protestants most often leave Jesus in the dust and run immediately to Acts 16:31 and Romans 10:9 to tell others how to get saved.
I suppose it is because they know Jesus was a legalist, and they realize that if they quoted him to others in the simplistic fashion that they quote Paul to others, the others will get the 'false' impression that salvation must be earned by good works (!?)
Would love to dialogue further with you about this.
Barry Jones
barryjoneswhat@gmail.com