In this opening scene, the three witches, or Weird Sisters (possibly Shakespeare’s version of the Fates?) convene and decide when to approach Macbeth and Banquo with their prophecy. They call on their “familiars” (companion spirits) and depart.

Shakespear presents the three witches meeting in the middle of a storm and preparing to entice Macbeth into evil, the riddling rhymes show that they are supernatural.

This scene is important because it immediately grabs our attention with its dramatic non-realism, raises our curiosity and expectancy, establishes the importance of the supernatural in the play and provides a clue to the key theme of good and evil.

The beginning of this scene is fairly brief, this helps to create a sense of mystery and wonder. Litlle is explained in this scene-A violent storm, three strange witches speaking in rhyme and waiting ominously for Macbeth.

The witches talk about Macbeth which makes the audience wonder about who is Macbeth which draws their attention in. “There to meet with Macbeth”. This draws the audience’s attention and interest, wanting to find out who Macbeth.
The Witches generally speak in rhymed couplets of trochaic tetrameter. These rhyme pairs create an incantatory (chantlike) effect.

One of Shakespeare’s key sources for the Witches in this scene was Reginald Scot’s The Discoverie of Witchcraft (1584):

[Witches] can raise and suppresse lightning and thunder, raine and haile, clouds and winds, tempests and earthquakes. Others doo write, that they can pull downe the moone and the starres. Some write that with wishing they can send needles into the livers of their enimies. Some that they can transferre corne in the blade from one place to another. Some, that they can cure diseases supernaturallie, flie in the aire, and danse with divels. Some write, that they can plaie the part of Succubus, and contract themselves to Incubus; and so yoong prophets are upon them begotten, &c. Some say they can transubstantiate themselves and others, and take the forms and shapes of asses, woolves, ferrets, cowes, apes, horsses, dogs, &c. Some say they can keepe divels and spirits in the likenesse of todes and cats.

–(Book I, Chapter IV), 246

According to J. A. MacCulloch (1929):

The AS wyrd is represented in English and Scots by “weird,” e.g., “he maun dree his weird” (suffer his destiny). Some link with Teutonic Fate-goddesses is therefore to be found in the “three weird sisters” of our earlier literature. Holinshed relates that three women “in straunge and ferly apparell, resembling creatures of an elder world,” met Macbeth and Banquo and foretold their destinies.

These women were either the weird sisters, that is the goddesses of destinie, or else some nimphs or feiries, endued with knowledge or prophecie by their Nicromanticall science.

They are Shakespeare’s witches or weird sisters, the Fatae or Parcae of Boece’s History. A story of “The weird Sisters” is mentioned in The Complaynt of Scotland, but it is now unknown, and the additions to Warner’s Albion’s England (106 A.D.) speak of “the weird elves,” as Spenser has “three fatal Impes” in his Ruines of Time, and Chaucer “the fatal sustrin” (sisters), akin to “the weird lady of the woods” in Percy’s ballad, who prophesied from a cave about Lord Albert’s child, then stole him away and nurtured him.

Whatever the ultimate origin of the Norns and similar dispensers of destiny may have been, they had human counterparts in actual prophetesses or magic-wielders, like the old Scots “spae-wife,” who foretold an infant’s future, or the Norse Spakona or Volva. In some references to these it is not easy to say where the human aspect ends and the supernatural begins. As Grimm says:

“…prophesying, inspiring and boon-bestowing women were always supposed to pass through the country, knocking at the houses of those whom they would bless, and tales of travelling gifting sorceresses were much in vogue all through the Middle Ages.”

A “bleeding Captain,” fresh from battle, tells King Duncan and his son Malcolm about Macbeth and Banquo’s battlefield heroics against rebels led by the Thane of Cawdor. He describes Macbeth’s slaughter of an enemy soldier in gory detail. The Thane of Ross enters with the news that Cawdor has surrendered and the rebels have been defeated. King Duncan orders that Cawdor be executed and Macbeth receive his title.

Like most of Shakespeare’s scenes, this one is written primarily in unrhymed iambic pentameter, otherwise known as blank verse (though notice the rhymes at the scene’s close). This contrasts with the previous scene, in which the Witches spoke primarily in rhymed iambic tetrameter.

From the 1971 Macbeth starring Jon Finch:
https://www.youtube.com/watch?v=BM6f7bflZDs