You shouldn't give out someone's phone number without permission.
Amy has a coworker who just expressed interest in her friend.
Amy wants to help her friend meet new people.
Amy talks to her friend about the coworker who is interested in her, highlighting his qualities.
Amy passes on her friends number to the coworker.
Amy's friend is interested and asks for his number.
Amy's friend is upset that she gave her number out to a stranger.