"Dismayed not this our captains, Macbeth and Banquo?"
"All hail, Macbeth, hail to thee, Thane of Cawdor!"
"Speak if you can. What are you?"
". . . To me you speak not. . ."
Shakespeare first introduces the Three Witches, where he made them behave very strangely. Even noting how they seem to think our world has its moral structure reversed. Before ending the scene the witches seem to have ill intention towards Macbeth.
". . . This supernatural soliciting cannot be ill. . ."
". . . The instruments of darkness tell us truths, win us with honest trifles, to betray us. . ."
We then meet the current King of Scotland, King Duncan who oversees the battle against the traitors and the Norwegians. Where a sargent reports that the Thane of Cawdor is a traitor and is defeated by his cousin Macbeth. Noting of his bravery and valor displayed. Which Duncan decides to name Macbeth the next Thane of Cawdor.
". . . Our eldest, Malcolm, whom we name hereafter the Prince of Cumberland. . ."
"The Prince of Cumberland! That is a step on which I must fall down, or else overleap, for in my way it lies. . ."
Speaking of Macbeth, Shakespeare soon after introduced him and Banquo a fellow brother in arms. They encountered the Three Witches (where before the encounter was called old hags by a sailor's wife who refused to share chestnuts with one of the witches who quickly faced a horrible fate showing more of their truly evil nature.), they prophcied Macbeth becoming the Thane of Cawdor (which already will happen) and became the king. Banquo is slightly envious of Macbeth for having given prophecies which before disappearing the witches gave him.
"My dearest love, Duncan comes here tonight."
"O, never shall that morrow see. . ."
After the witches leave the pair discuss the prophecies they were both given which while as supernatural and untrustworthy the witches seemed (which Shakespeare clearly and highly shown to the audience). Macbeth seemly becomes extremely intrigued by the prophecies and to find two men arrive to tell them of the Thane of Cawdor's betrayal and Macbeth's ascension to become the Thane of Cawdor.
They return to greet King Duncan who welcomes them both with wide open arms. Where Shakespeare showcases Duncan's kindness towards his subjects and his fondness of his fellow men. He also names his eldest son Malcolm the heir to the throne of Scotland. Macbeth who begins to become obsessed with the prophecies intends to fulfill it quickly by any means beginning to shed light on his darkest desires.
But, before Macbeth left the scene. Duncan decides to go to Macbeth's Castle for the night. So, Macbeth sends a message ahead to his wife. Who we soon meet, Shakespeare introduces her as an utterly ruthless and ambitious woman who even managed to convince her reluctant husband (Shakespeare shows that he hasn't succumbed to his flaws and greed fully) to commit regicide.