In the New Testament, God never* commands His people to be something that they aren’t. Rather, He tells them to stop being something they are not. All the commands for holiness are simply commands to be who you are. God’s people are regenerated - given a new heart and sanctified - given a new nature. Therefore, in commanding us, God tells us to stop pretending we are something that we are not - slaves to sin - and actually be the men and women we are - slaves to righteousness.
*Never as far as I know, but feel free to prove me wrong. If you can give me an example, I’ll happily change never to rarely.