Similarities between Banquo and Macbeth are as follows:
Banquo and Macbeth are both similar in station at the beginning of the play. They are both Scottish generals in the king's army and help Duncan defeat the King of Norway.
Together, Banquo and Macbeth encounter the Witches and receive a prophecy about their future.
Both Banquo and Macbeth die violent deaths.
Despite their multiple similarities, Banquo and Macbeth have many differences.
For example, Banquo dismisses the witches' prophecies as a work of evil, refusing to be drawn in by their tempting words; on the other hand, Macbeth deeply considers the meaning of their speech.
Another key contrast between the two men is that Macbeth actually acts on the witches' words, whereas Banquo chooses not to involve himself with postential mischief.
Banquo has a son; Macbeth does not have any living children.
Firstly, the similarities between the two men at the beginning of the play are that they are both generals in King Duncan's army, fighting the invading forces of the king of Norway and the traitors, Macdonwald and the thane of Cawdor. They are both courageous and respected. They are both admired by not only their men but also by their king. They are both seen as noble and honorable. Both men are, at the start, loyal to their king and country.
It can also be said that both men are naturally suspicious and wary of any possible threats, though for different reasons. Banquo becomes suspicious of Macbeth for he believes that he has taken the witches' predictions too much to heart. He, for example, tells Ross and Angus about Macbeth:
New horrors come upon him,
Like our strange garments, cleave not to their mould
But with the aid of use.
He later also tells Macbeth the following in Act 2, scene 1, when the two speak and Macneth promises that he will ensure Banquo certain benefits if they keep counsel:
...but still keep
My bosom franchised and allegiance clear,
I shall be counsell'd.
Banquo is, in effect, telling Macbeth that he will stay loyal to his king, but will listen to what he has to say. This also clearly indicates that he does not have the same ambitions which Macbeth seems to possess. Macbeth's suspicions are later born from his paranoia, when he deliberately seeks out and destroys whomever he believes is against him. His suspicions serve only himself, whilst Banquo's are for the general good.
Their differences are quickly exposed when the two men encounter the three witches on the heath after their victorious battle. They are greeted differently by the weird sisters. The witches greet Macbeth with his original title, thane of Glamis, and add another, thane of Cawdor. They tell him that he shall be 'king hereafter.' They greet Banquo in a paradoxical fashion:
Lesser than Macbeth, and greater.
Not so happy, yet much happier.
Thou shalt get kings, though thou be none:
So all hail, Macbeth and Banquo!
Their responses to the witches' predictions are also different. Macbeth is enthralled to such an extent that he provokes Banquo to comment that he is 'rapt withal.' Banquo, however, is skeptical and does not attach much value to what they say. He later warns Macbeth about giving too much credence to their predictions.
But 'tis strange:
And oftentimes, to win us to our harm,
The instruments of darkness tell us truths,
Win us with honest trifles, to betray's
In deepest consequence.
When Macbeth is informed by Ross that he has been given the title of the soon-to-be-executed thane of Cawdor, he is overawed. This piece of good news allows us insight into another marked difference between him and Banquo. Macbeth exposes his ambition, whilst Banquo does not, at any point, indicate the same. In an aside, Macbeth clearly expresses his desire to be king, stating that it seems as if destiny is favoring him and he may, after all, not have to do much to achieve his 'overriding ambition' as indicated in the following extracts:
Glamis, and thane of Cawdor!
The greatest is behind.
If chance will have me king, why, chance may crown me,
Without my stir.
In their meeting with King Duncan, another difference is noted. Duncan has rewarded Macbeth for his bravery and loyalty by bestowing a title upon him, whilst Banquo receives no such material reward. It does appear, however, that Duncan bears greater affection for Banquo, whom he embraces warmly, whilst Macbeth is not greeted in a similar fashion.
That hast no less deserved, nor must be known
No less to have done so, let me enfold thee
And hold thee to my heart.
This may be an indication that the king is wary of Macbeth.
Banquo is generally depicted as kindly, loving and loyal. Macbeth, on the other hand, generally ignores Lady Macbeth once he is embroiled in his malice. He instructs the doctor to cure her of her illness instead of being at her side. Later, although he expresses sentiment at her death, it is clear that he has been so overwhelmed by malevolence that he has practically lost all compassion. He has become hard and cold.
Finally, although both men die gruesome deaths, only one of them is responsible for their fates. Macbeth had Banquo murdered and he is the source of his own doom for he is killed and then beheaded by Macduff in an act of vengeance for the murder of Banquo's family on Macbeth's instruction.