This excerpt is from Shakespeare 'The Tragedy of Macbeth'.
Explanation:
A harbinger is a messenger who foresees something which is going to happen in the future. The strong sense of movement and of impending threat is generated throughout Act V by the swift alternation of scenes.
He says, 'Those clamorous harbingers of blood and death'. It is a sign of what is to come. A precursor or destiny of fate.
Macbeth says, 'I'll be myself the harbinger and make joyful'. This means he will go and inform his wife that Duncan was coming.
