How does Shakespeare's use of the specific simile I am constant as the Northern Star support the statements he makes in the rest of his speech?

In the speech where Shakespeare uses the simile "I am constant as the Northern Star," it underscores the speaker's unwavering resolve and reliability amidst chaos. The Northern Star, known for its fixed position in the night sky, symbolizes steadfastness and guidance, contrasting with the fickleness of others. This comparison enhances the speaker's assertion of their steadfastness and integrity, reinforcing their commitment to their beliefs and principles despite external pressures. Thus, the simile serves to elevate the emotional weight of the speech, emphasizing the theme of loyalty and constancy.