[Morthoron]

Originally Posted by Rhod the Red

Yes, the Istari were representatives of the Valar, though in the unofficial sense. Because their mission was secret with restrictions on their uses of Magic, etc.

Originally Posted by J.R.R. Tolkien, Letter #144

They were thought to be Emissaries (in terms of this tale from the Far West beyond the sea), and their proper function, maintained by Gandalf, and perverted by Saruman, was to encourage and bring about the native powers of the enemies of Sauron

and -

Originally Posted by J.R.R. Tolkien, Letter #145

I am sure you are right: Gandalf was of course always old. He was an Emissary, who had that shape from the first...

and again -

Originally Posted by J.R.R. Tolkien, Letter #153

The power of the Ring, over all concerned, even the Wizards or Emissaries, is not a delusion - but it is not the whole picture...

and yet again for added emphasis -

Originally Posted by J.R.R. Tolkien, Letter #156

...[Gandalf] with the other Istari, wizards, 'those who know', an emissary from the Lords of the West, sent to Middle-earth, as the great crisis of Sauron loomed on the horizon.

and one more time to bludgeon you with the facts -

Originally Posted by J.R.R. Tolkien, Letter #153

The istari are translated 'wizards' because of the connexion of 'wizard' with wise and so with 'writing' and knowing. They are actually emissaries from the True West, and so immediately from God, sent precisely to strengthen the resistance of 'good', when the Valar became aware that the shadow of Sauron is taking shape.

In three instances, Tolkien's capitalization of "Emissaries" and "Emissary" clearly indicates a title and official nature of their secret mission. There are four more instances of Tolkien using the words emissary or emissaries in regards to the istari in his letters.