In Act I, scene 2 of Macbeth, King Duncan waits for news from a battle in which Macbeth and Banquo led the Scots against the Irish. Duncan is informed by one of the noblemen that the traitorous thane of Cawdor provided aid to Norway against Duncan:

Where the Norweyan banners flout the sky
And fan our people cold. Norway himself,
With terrible numbers,
Assisted by that most disloyal traitor
The thane of Cawdor, began a dismal conflict (Act 1, Scene 2)

With Cawdor's capture, Duncan sentences him to death and decides to award Cawdor's title to Macbeth for having fought so valiantly in the battle.

Beyond Cawdor’s sentencing, Macbeth contains three more death sentences or orders.  The three vile witches, “black and midnight hags” use their magic to make predictions leading Macbeth to murder Duncan as well as order the deaths of Banquo and Fleance.  Duncan, Banquo, and Fleance were all premeditated murders or death sentences as well (although Fleance escapes death).

"black...hags" from Act 4, Scene 1, line 48