They are associated with blood and death because in the play they are tools by which many murders are commited. Because hands are associated with blood they are also associated with guilt.
a. Soldier ; which ne'er shook hands, nor bade farewell to him, Till he unseam'd him from the nave to the chaps And fix'd his head upon our battlements (1.2.23-25)
b. Macbeth never shook hands with him, or bade him farewell, he cut him open from his navel to his jaws and put his head on a stick. Macbeth's loyal actions on the battlefield.
c. First quote no comparison yet. A soldier is describing loyal and brave Macbeth's victories on the battlefield as he fights for the King and Scotland.
a. All: The weird sisters, hand in hand, / Posters of the sea and land, / Thus do go about, about; Thrice to thine, thrice to mine, And thrice again, to make up nine. / Peace! The charm's wound up.
b. The fortellers of fate, swift travellers of the sea and land, we get around, 3 times for you (for one witch) , three times for me (another which), and tree times again to make up nine (3 times for each witch). Stop! The spell is over. The three witches are holding hands to conjure up the spirits, evil and their strength so they can put a spell over a sailor's ship because his wife has upset one of the witches.
c. In the first passage Macbeth forwent the usual battle greetings and did not shake hands with his enemy, just raised his sword and...