The Power of Invitation

Invitation to contribute can demonstrate interest.
Invitation to a party can demonstrate care.
Invitation to carry responsibility can demonstrate trust.

Joining a party without Invitation is called Gatecrashing.
Helping a person without Invitation is called Meddling.
Entering a house without Invitation is called Intrusion.

1. When does a Prophet need an Invitation to speak?
2. When does a Missionary need an Invitation to go?
3. Who does a Leader expect an Invitation from?