Lukewarm Laodicean saints. Neither cold nor hot, unusable. God wanted them to be cold or hot (Laodicea was known for both its cold and hot water springs) therefore this does not refer to emotion, or passion, or being "on fire for God." God wanted them to be usable, either a cool drink of refreshing water to a thirsty soul, or a warm bath of soothing energy to a tired soul.
And Jesus stands at the door and knocks, He wants to have fellowship with them, to be at home in their church, to eat with them. He wants to have individual intimacy with any who will be with Him.
This is not an initial salvation passage about "asking Jesus into your heart" (Christianese if I've ever heard it).
This is wonderful intimacy with God. Repentance of sin and reconciliation and confession and significance by being aligned with God our creator, the faithful and true who wants to "counsel you to buy from me gold refined by the fire, so you can become rich; and white clothes to wear, so you can cover your shameful nakedness; and salve to put on your eyes, so you can see."
