Macbeth 5.3 Performance: Macbeth, Lines 1-10

Macbeth reflects on the prophecy that he is invulnerable to any man born of a woman. He questions Malcolm's birth and fate, reassured by spirits that he is safe. Despite the threat of English forces, Macbeth remains defiant and resolute, confident in his invincibility.

What does the phrase 'no man that's born of woman shall have power upon thee' imply about Macbeth's invincibility?

Discuss the meaning of 'The mind I sway by, and the heart I bear shall never sag with doubt, nor shake with fear.'