Imamah (Shia doctrine)
By the verse Quran, 2:124, Shias believe that Imamah is a divine position always Imamah is accompanied by the word guidance, of course a guidance by God's Command.A kind of guidance which brings humanity to the goal. Regarding 17:71, no age can be without an Imam. So, according to the upper verse 1.Imamah is a position which is appointed by God and must be specified by Him 2.Imam is protected by a divine protection and no one exceles him in nobility 3. No age can be without an Imam and finally Imam knows everything which is needed for human being to get to the truth and goal.

Q: What is an Imam protected by?
divine protection