the spirit teaches you family speech

Adoption, heir, inheritance. Paul reaches for family and legal words, and Heiser argues he is doing something specific with them: describing the Church as the reconstituted divine-human family of God. Not a club you joined. A household that was broken and is being put back together.
That is why the Spirit teaches you to say Abba. It is family speech. And Paul runs it straight on into inheritance - if children, then heirs - because the destiny in view is what Adam and Eve were made for in the first place: glorified imagers of God, living in his presence as his children.
Scripture links:
- Romans 8:15-16 - "you have received the Spirit of adoption as sons, by whom we cry, 'Abba! Father!' The Spirit himself bears witness with our spirit that we are children of God."
- Romans 8:17 - "and if children, then heirs - heirs of God and fellow heirs with Christ."
You are not being tolerated in the house. You are being taught to talk like you live there.