To be in Adam is to belong to the humanity born into the rebellious order Adam established — alienated from God, structured around self-rule, and subject to death.
Every person enters life east of Eden, within a humanity already bent away from God’s rule and already under death’s reign. This is not a neutral starting point later spoiled by choice; it is the inherited human condition. Yet no one is merely a victim: each morally responsible person personally confirms Adam’s rebellion through his own sin.
Christ alone entered Adam’s world without making Adam’s choice, and He delivers from the old humanity all whom the Spirit joins to Him. The only escape from being “in Adam” is to be “in Christ.”
See in Scripture: Romans 5:12–21; 1 Corinthians 15:21–22; Ephesians 2:1–3; Romans 6:1–11