Craig Fisher lays out a case why Ephesians 1 is not about “individual salvation”. The conclusion:
Is a person chosen in Christ “before the foundation of the world” or “after believing?” When Paul says the “us in Him” he is referring to the body of Christ. The individual members of the body of Christ are not chosen until they exercise faith and are sealed with the Holy Spirit. The corporate group is chosen to be holy and blameless before Him. We do not know who is in this group until much later than the foundation of the world.
Maybe an analogy will help. The director says “the band is really fortunate this year, we will play in Hawaii this winter.” Of course each band member has to try out for their chair in the band. There remains a competition to determine who is going to be in the band. The individual members have not yet been determined. The corporate entity, the band, will go to Hawaii.
God chose the body of Christ to be holy and blameless before Him in love. The body of Christ is the “us in Him.” The individual members of the body have yet to be determined.