When does Satan accuse believers before God?
Satan accuses believers before God the Father every time they sin, because he still has access to the throne room of heaven. He will continue this until the midpoint of the tribulation, when he is cast out for the last time, and Jesus Christ advocates for believers as their attorney.
Les explains that Satan has had access to the very throne room of heaven and will have it until the midpoint of the tribulation, when he is cast out for the last time. He is the accuser of the brethren, accusing believers before God the Father every time they sin. But believers have an advocate, an attorney—Jesus Christ the righteous—who says they are under the blood, purchased and His. This is the advocate with the Father in 1 John 2:1, and verse 2 adds that He is the propitiation for our sins and the whole world.