Let us keep this simple.
Yahshuah kept the law as it was before he was crucified. Once he had ''fulfilled'' the law through his proper sacrifice (of Cain) then there was a new priesthood and a change in the law (Hebrews).
Thus, the Saviour, through Paul, expanded the law as it should be: maliable, alive, living, active, not just words on stone. It is Paul who expanded this.
Yahshuah's sacrifice crucified the Mosaic understanding of the law.
It was not the law that was wrong, it was man's interpretation of it that was wrong. The Saviour put that right and expanded that thinking through Paul.
Thus the words would be different when comparing Paul's writings with the gospels, as after the crucifixion it had changed.
But if you reject Paul, you reject the freedom you have in the law through the Spirit, you reject the freedom you have in Christ, and therefore you are still under the old Mosaic law. That means you are under a curse as that law led to death.
For example, Christ died ''for ALL'' which means all died and therefore all must be resurrected. Thus those dead before are alive now, and thus we see that there is a reincarnation of souls and indeed, the universe itself. That is why Paul mentions nothing about the valley-of-hinnom (Hell) but only Hades (grave) which we are brought from at some point in time.