Scrum Master Analogy

The ScrumMaster is there to help the team in its use of Scrum. Think of the help from a ScrumMaster as similar to a personal trainer who helps you stick with an exercise regimen and perform all exercises with the correct form. A good trainer will provide motivation while at the same time making sure you don’t cheat by skipping a hard exercise. The trainer’s authority, however, is limited. The trainer cannot make you do an exercise you don’t want to do. Instead, the trainer reminds you of your goals and how you’ve chosen to meet them. To the extent that the trainer does have authority, it has been granted by the client. ScrumMasters are much the same: They have authority, but that authority is granted to them by the team.

source: https://www.mountaingoatsoftware.com/agile/scrum/scrummaster