Romans 8:9
But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his.
Primary
What this passage establishes
Belonging to Christ requires the indwelling Spirit of Christ.
Why it matters in the argument
Acts gives observable accounts of people receiving the promised Spirit. Those narratives supply the Bible’s clearest pattern for recognizing Spirit reception.
Apostolic connection
Apostolic teaching distinguishes the initial sign of tongues when the Spirit is received from the later congregational gift that requires interpretation.
Common misunderstanding
Paul’s question ‘do all speak with tongues?’ concerns distributed gifts in the assembled body, not the repeated initial sign in Acts.
How to use it in conversation
Start with the promise, then compare Acts 2, 10, and 19. Use 1 Corinthians only after distinguishing initial sign, private prayer, and public gift.