Are there some examples in the play Macbeth that show that the three witches are evil?(i.e. Specific lines of theirs or Hecate's)

It is important to note that in Shakespeare's time, there
was quite a furor over witches and witch-hunting.  We, in the US, know something of this
story from the events surrounding the Puritans of Salem and their famous witch trials. 
So, for the average God-fearing citizen, alive when Macbeth was
written, witches were considered a thing to be feared, and there was certainly paranoia
about having a witch curse you with black magic.

The
question of evil is a major theme in the play Macbeth, and could be
considered, like Beauty, to be in the eye of the beholder.  The witches cast
spells:

Round
about the cauldron go;

In the poison'd entrails
throw...

Boil thou first i' the charmed
pot.

They call their
familiars (animal assistants) in the opening scene -- "I come, Graymalkin;" "Paddock
calls."  And both the cauldron of magical goo and the animal familiars are strong
signifiers of witches who perform evil deeds. But does this prove
that they are evil?  It is hard to say.

It might be true
that the witches, by a preponderance of evidence, are evil, but the question that
concerns the play more would still remain:  Are the witches and their charms responsible
for Macbeth's behaviour, or is Macbeth a free agent, acting with his own free will? 
This, more than whether the witches themselves are evil, is the question that seems to
permeate the play.