You need to understand that the believers today as well as the indwelling of the Holy Spirit will be taken from this world at the rapture. The last seven years (the tribulation) will be more along the lines of the old covenant. It WILL be important for people during that seven years to focus on their acts/works because there will be no indwelling or “Christ in them”.
I meant to ping you to 76.
That, however, does not address the early church which was largely Jewish. Even in Paul’s epistles he says both circumcised and uncircumcised alike are under Grace. Even the trib saints will be saved by Grace through faith. This side of the Cross it is always the shed Blood of Christ.