Why does Romans chapter 6 say we are not under law but under grace?
Because God sent Saul of Tarsus to the Gentiles after Israel rejected Christ, Paul writes believers are not under law but under grace. This transition came as Judaizers from Jerusalem tried to impose Mosaic law and circumcision on Gentile converts.
Les explains that Israel had been under the covenant promises and the law, but when their Messiah appeared and presented Himself as King, Redeemer, and Messiah, the nation rejected Him and crucified Him. In Acts, Peter repeatedly appealed to Israel to repent, yet Israel continued in unbelief. Then in Acts chapter 9, God supernaturally saved Saul of Tarsus, the arch-religionist and zealot, and announced He would send him far hence to the Gentiles. That is when everything began to change, and that is why the graphic statement in Romans chapter 6 had to be made: believers are not under law but under grace. As Gentile converts came under the Gospel, Judaizers from Jerusalem undermined it, insisting Gentiles must keep the Law of Moses and be circumcised. The Galatians were falling to that, and Paul made a stringent statement about it, which he reviews in Galatians chapter 1.
For sin shall not have dominion over you: for ye are not under the law, but under grace.
What does it mean that believers are not under the Law but under Grace?
Romans 6:14 declares that sin shall not have dominion because believers are not under the Law but under Grace. This means they are not under the ritual, stipulations, and demands of Judaism; those have been set aside. Grace is not license, and love in daily experience fulfills the Law.
What does it mean to not be under the Law?
This means the ritual and stipulations of Israel's Law and the demands of Judaism have been set aside, so sin no longer has dominion. Believers are now under Grace, not license, and love fulfills the Law. The old Adam cannot rule over those under Grace.