>>293
>It's almost like the Mosaic Covenant applied to the people of Moses,(...)
It's almost like you've lost the track of the conversation. Neighbour in the Law is a fellow Hebrew since 'thy people'. Neighbour in Jesus' teaching is your fellow human being, not just your fellow Christian.
>but the line "hate thine enemy" is nowhere to be found in the entire Old Testament.
It is a summary of the message of the Law, not a direct citation.
>Acts 21:26
Interesting, I didn't remember that. And yet in verse prior you read those who advised Paul to perform the rituals say
"'And concerning those of the nations who have believed, we have written, having given judgment, that they observe no such thing, except to keep themselves both from idol-sacrifices, and blood, and a strangled thing, and whoredom.' "
And if Levitical Law was taught by Jesus then gentile is less of a Christian than Hebrew here.
And while it might seem like mental acrobatics what Paul did there does fit 1 Corinthians 9:20
"and I became to the Jews as a Jew, that Jews I might gain; to those under law as under law, that those under law I might gain;"

>Just because we're saved, it doesn't mean that sin isn't a problem anymore.
When Paul wrote about it he made separation between body and internal man. Your body will die (or will be transformed if you live through to see Jesus' return) your internal man is saved already. Dynamics of wrongdoing is entirely different than back under the Law. How you lead your life is not without importance but if you've built on a foundation of Jesus you are saved -> 1 Corinthians 3:15. But you need to understand - you don't build with works of the Law but with labour of Love. Law is a different foundation.