Before the beginning, the true eternal and infinite Trinitarian God entered into an eternal mutual agreement or covenant - the Father with the Son and both with the Spirit. In this covenant, certain ones yet to be created were considered to belong to the Son and so set apart to him. At that time the detail of how this would be brought about was agreed. Whether these chosen ones were seen as sinners or not is unclear. The essential thing about this covenant is that it was a covenant of grace not works.
