Final answer:
The weird sisters in the witch's tale of the sailor's wife are portrayed as malicious, powerful, and capable of unnatural acts, confirming their role as menacing entities within the play.
Step-by-step explanation:
The witch's tale of the sailor's wife is indicative of the weird sisters' malignant nature. These witches are presented as powerful, malicious entities with the ability to influence and meddle in human affairs, as highlighted by phrases like "A sailor's wife had chestnuts in her lap" and the assertion that one witch will sail in a sieve to follow the sailor's husband. They are not just users of dark magic but also figures of ominous portent, defying the natural order with actions like sailing in a sieve, which implies a supernatural ability to overcome the limitations imposed by nature. Historical literature often depicts witches as malevolent figures associated with harming others, influencing their behavior negatively, and even being part of terrifying events, reinforcing the idea that these characters in the play are to be seen as threats with the power to unbalance the natural and social order.