What evidence is there for Macbeth to do what he wants to achieve the power he thinks he deserves?a quote would be helpful thankyou

In Shakespeare's Macbeth, the
evidence that Macbeth uses to convince himself that he deserves the power and authority
he obviously wants (to be king) comes in two parts. 

First,
the witches predict that he will be Thane of Cawdor and
king:

All
hail, Macbeth!  Hail to thee, Thane of
Cawdor!

and

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All hail, Macbeth, that shalt be king hereafter! 
(Act 1.3.49-51)

The idea of
being king may or may not be present in Macbeth's mind before these predictions, but it
is certainly in his mind after these predictions.  The witches predict that he will be
king, and he definitely is interested in being so.  This is step
one.

Step two comes when the first prediction, that he will
be Thane of Cawdor, comes true:

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...for an earnest [a deposit] of a greater
honor,

He [the king] bade me, from him, call thee Thane of
Cawdor;

In which addition, hail, most worthy
thane,

For it is thine.  (Act
1.3.105-108)

Macbeth uses the
coming true of this first prediction, as evidence that the second prediction will also
come true.

Of course, the witches are equivocating (telling
him half-truths, or telling him truths that can be interpreted multiple
ways). 

Ironically, Baquo warns him just a few lines later
that sometimes "the instruments of darkness" tell us a little thing that comes true, in
order to make us believe something larger will come true, and thereby doom us, but
Macbeth completely ignores this, and interprets the evidence exactly as he wants
to.