Tolkien aborda isso na Carta 156:
[Gandalf] was the only person who could direct the resistance to Sauron successfully, and all his mission was vain.
[...]
The 'wizards', as such, had failed; or if you like: the crisis had become too grave and needed an enhancement of power. [...] [Gandalf] was sent by a mere prudent plan of the angelic Valar or governors; but Authority had taken up this plan and enlarged it, at the moment of its failure.
The Letters of J.R.R. Tolkien 156: To Robert Murray, SJ (draft). November 1954
A promoção de Gandalf foi uma decisão feita por Deus para compensar o poder crescente de Sauron e o poder de enfraquecimento do Povos Livres da Terra Média.