Why does Gandalf even draw a sword?

Question

When Gandalf goes to Dol Guldur while he searches for traces of the Necromancer. He draws his sword.

But in the later part of the scene he uses his staff to fend off Azog and the other evil there, so why the need for the sword in the first place?

Answer 1

There's no canon answer to this question, but it also doesn't really need one.

It's clear from his exchange with Radagast that Gandalf knows Dol Guldur is a dangerous place for him to be:

Radagast: Wait, Gandalf! What if it's a trap?

Gandalf: Turn around, and do not come back. It's undoubtedly a trap.

^{The Desolation of Smaug (2013)}

He's walking into an environment filled with:

• Unknown danger
• Lots of places for Unknown Danger to hide and take him unawares

It appears that Gandalf only uses his staff against Azog because he wants information, but how did he know there would be anything there to give him information? For all he knows, Sauron has filled the place with Giant Spiders, or hungry Wargs, or trolls, or any number of evil creature not disposed towards conversation.

Gandalf is just demonstrating sound survival skills by being prepared for anything that might be waiting for him.

Answer 2

It looks to me (from that clip) like he goes in expecting to use both staff and sword (or, at least, prepared to do so), but he gets disarmed at the 1′25″ point.  He manages to hold on to the staff, but he doesn’t get a chance to go back and retrieve the sword until after the fighting is over.

Answer 3

In researching this, there is actually a canon reason I believe, that Gandalf always carries a sword only to use his staff when in dire trouble.

It seems that due to him being a Istari (In Quenya "wizard") (Also See books ,The Silmarillion And The Unfinished Tales) ,which are Maiar spirits in human form sent help against the threat of Sauron to Middle-Earth.

In the Unfinished Tales It was the Council of the Valar that said they were ,

forbidden to reveal themselves in forms of majesty, or to seek to rule the wills of Men and Elves by open display of power, but coming in shapes weak and humble were bidden to advise and persuade Men and Elves to good

And this,

clad in bodies as of Men, real and not feigned, but subject to the fears and pains and weariness of earth, able to hunger and thirst and be slain; though because of their noble spirits they did not die, and aged only by the cares and labours of many long years.

These two exerts clearly show that Gandalf being an Istari, that he was supposed to act like a man and with fears of a man. So his limited use of a sword was in my eyes, was sort of a facade of sorts so that Gandalf was not to reveal his true identity. To show that he was just as vulnerable as everyone else, when in fact he was not. And when really in trouble he would fall back on his powers as a wizard.