Lord Of The Rings: 10 Things You Didn't Know About The Wizards
4. Gandalf Was Always Greater Than Saruman
From the time Gandalf and Saruman arrived in Middle-earth they were set to the task of fighting the forces of Sauron. Due to Saruman's role as the head of the White Council, many have often considered him the more powerful of the two wizards.
But in Tolkien's extended writings this doesn't seem to be the case. When the Valar sent the wizards to Middle-earth, they arrived at the Grey Havens. The elven lord CĂrdan was wise enough to perceive who the wizards really were, and recognised Gandalf as the most powerful, or at least the most wise. He gifted him one of the three elven rings of power to aid in his struggle.
Although Saruman was not corrupted for many years, this was what started his jealously of Gandalf. Years later when the White Council was assembled, Galadriel urged Gandalf to become their leader, but he declined. Only then did Saruman take up the role.
It's often thought that the colour of a wizard denotes some kind of rank. But it's more like each colour represents some kind of role. The Grey Wizard was required to travel amongst the enemies of Sauron and encourage them, whereas the White was required to lead them.
When Gandalf eventually becomes the White Wizard he certainly becomes more powerful, but it's not some kind of promotion; rather he's filling the role that Saruman was unable to.