The legal background to Paul’s adoption language (Rom 8:15, Gal 4:5, Eph 1:5).
Under Roman law, an adopted son held every right of a natural-born son. The father’s name. The inheritance. A place in the family.
His old legal identity fell away, along with its obligations.
Paul was writing to a church in Rome. His readers would have heard adoption as a legal transfer into a new family, with full standing.