It's gonna take the destruction of our bodies . God couldn't save the old man . He had to create a new one. And that ye put on the new man, which after God is created in righteousness and true holiness. God's holiness and justice demanded this.
Salvation comes with much difficulty.
And hereby we do know that we know him, if we keep his commandments. The Bible doesn't speak of any other way. The next verse says it all. Jesus Christ is Truth and if Truth is not in us then we are not in Him. But you say, James says we will sin after salvation .