LotR -- Book 2 - Chapter 04 - A Journey in the Dark

[Tuor of Gondolin]

In reference to comments above about Gandalf's fallibility in this chapter and
the wolves possibly being Maiar, it's interesting how Maiar have far more
direct influence on Middle-earth history then Valar: Melian, Gandalf, and
Radagast, and on a somewhat less positive side Sauron,
Saruman, and Balrogs. Any intervention by Valar are, even when
significant, like Ulmo with Tuor, fleeting, presumably because of the
overwhelming influence they would exert otherwise (as Melkor did when he
insisted on prolonged interaction with Middle-earth). It was the (relative)
weakness of Sauron vis-a-vis Melkor, further diluted by his putting much of
his power into the Ring, that made resistance feasible against him. And while
the Istari

were forbidden to reveal themselves in forms of majesty, or to seek to rule the wills of Elves and men by open displays of power

(UT)
even Melian had clear restrictions on power and knowledge (not even knowing
of events in Valinor after she left).
Gandalf does generally act, even as Gandalf the White, largely as an
adviser (and without even once whacking any Gondorian with his staff ). That he has to reveal his powers at times (Caradhras, the
wolves, the Balrog, shows just how desperate events had become, partially
because of the betrayal of their mission by Saruman.