Romans 14:17-18 — For the kingdom of God is not meat and drink; but righteousness, and peace, and joy in the Holy Ghost.
For he that in these things serveth Christ is acceptable to God, and approved of men.
Kingdom (here) — sphere of God's rule — where His rule is acknowledged — His rule over our hearts.
The unsaved will see the outward effects when one is experiencing righteousness, peace, joy in the Holy Spirit.
The kingdom is not rules.