Loyalty and guilt are also strong themes in Macbeth. Duncan clearly values loyalty – he has the first Thane of Cawdor executed and rewards Macbeth by making him the new Thane.
Shakespeare cleverly uses loyalty as a dramatic device as well – Duncan is in the middle of talking about
absolute trust (Act one, Scene four, Line 14) when Macbeth walks in.
We know he's already thought about killing Duncan, but for the moment he talks about
the loyalty I owe (Act one, Scene four, Line 14) and his
duties (Act one, Scene four, Line 24) to Duncan.
Loyalty is also very important to Banquo – he will not desert Duncan. Macbeth, however, has an odd idea of loyalty – he knows he is doing the wrong thing, but he still goes ahead.
Early on in the play perhaps it is his wife who is manipulating him, but later on it is Macbeth who makes the decisions. And later on he also starts to show he hates disloyalty, threatening his messengers and servants.
Macbeth also shows his guilt – he is unsure before the murder and regrets it immediately after. Lady Macbeth is the opposite – she seems to show no guilt at the time and even talks about how
a little water (Act two, Scene two, Line 64) cleans away the blood.
Her increasing madness later on is a sign of her guilt and she imagines her hands to be stained with blood.