Final answer:
Macbeth initially contemplates becoming king as a matter of chance but later on becomes actively involved in seizing power. His primary focus is on becoming king rather than on who his successors might be.
Step-by-step explanation:
The question revolves around the character of Macbeth in Shakespeare's play and his reaction to the possibility and later certainty of becoming king. At first, Macbeth seems to be okay with the idea of becoming king through chance, as suggested by his line, "If chance will have me king, why, chance may crown me, Without my stir." This indicates he is not planning to take action to make it happen. However, as the play progresses, Macbeth's ambition is stoked by the witches' prophecy and his wife's encouragement, which leads him to take active steps to ensure his ascension to the throne. He does not express concern for his lineage or sons taking over the throne after him; his focus is on immediate power and status.
Furthermore, the interactions with Banquo reveal Macbeth's growing obsession with power. When Macbeth notes, "Your children shall be kings," it highlights that even though Banquo's lineage is prophesied to reign, Macbeth is first and foremost concerned with his rise to power. By the time he becomes king, he is deeply involved in the machinations of power and fears losing the throne, which could imply he is less concerned about his successors and more about holding onto power himself.