The short answer the texts give is: you cannot fully be what you are made to be without one — not because a rule requires it, but because the thing itself requires it. The New Testament has no category for a solitary Christian. The New Testament word for "church" literally means "assembly" — it names a gathered people, not a spiritual posture. The body-of-Christ language in Paul is not metaphor-for-convenience; it is a claim about structure: a body with one member is not a body, and the eye cannot say to the hand "I have no need of you" (1 Corinthians 12:21). The gifts are distributed among the members precisely so that no single person can function as the whole — interdependence is the design, not the inconvenience. Hebrews 10:25's "not neglecting to meet together" is set inside a passage about holding fast under pressure; the community is described there as the mechanism of mutual encouragement, not an optional supplement to private faith. And the arc of the whole story ends with a city — the image is irreducibly communal. The hope is not individual souls floating free; it is a people, together, dwelling with God. Read and test this in the passages below before taking the briefing's word for it.
1 Corinthians 12:12–27 — the body metaphor worked out in detail; interdependence as design, not deficit
Hebrews 10:19–25 — "not neglecting to meet together" in context; the community as the encouragement mechanism
Ephesians 2:19–22 — you (plural) are being built together; the building requires the stones to be placed
Acts 2:42–47 — the first description of what the gathered life looks like in practice
Revelation 21:2–3 — the final image is a city, not a flight; the hope is communal, not individual escape
Don't take this briefing's word for it — read these and test it.
Most traditions agree the gathered church is normative; they differ on how tightly obligatory and what counts. Catholic and Orthodox traditions: the church is not optional — it is the Body, and the sacraments require it; you cannot bracket the assembly without bracketing the Eucharist. Mainline Protestant: gathered community is essential in principle, with pastoral flexibility in practice. Evangelical/low-church: the priority is real relationship over institutional form — a small group, a house church, a congregation all qualify. All of these, even the most flexible, resist the idea that private belief alone is sufficient.
This question reads inward — which is exactly right. This lens reads texts and traditions, not the person asking. Whatever your history with churches has been, that history is yours to name, not mine to grade.
This question deserves a real conversation with someone who has skin in the game — a pastor, a priest, a person who belongs somewhere and can tell you honestly what that costs and what it gives. The map-room can point; the room itself is somewhere else.