What does King Duncan decide to do because Macbeth has fought heroically for him?William Shakespeare's "Macbeth"

First, after Duncan learns that Macbeth has defeated the forces of a traitor, the Thane of Cawdor, the king decides to have Cawdor executed and to give Macbeth his title (Act 1, Scene 2):

DUNCAN:

No more that Thane of Cawdor shall deceive

Our bosom interest. Go pronounce his present death,)

And with his former title greet Macbeth.

ROSS:

I'll see it done.

DUNCAN:

What he hath lost, noble Macbeth hath won.

Then, after victory is declared, the King speaks to, among others, his son Malcolm, Banquo and Macbeth. He is overjoyed by the turn of events and invites himself to dinner at Macbeth's castle at Inverness (Act 1, Scene 5):

DUNCAN:

My plenteous joys,

Wanton in fullness, seek to hide themselves

In drops of sorrow. Sons, kinsmen, thanes,

And you whose places are the nearest, know

We will establish our estate upon

Our eldest, Malcolm, whom we name hereafter

The Prince of Cumberland; which honor must

Not unaccompanied invest him only,

But signs of nobleness, like stars, shall shine

On all deservers. From hence to Inverness,

And bind us further to you.

A fatal mistake for old King Duncan.