Final answer:
The phrase "if you take the king's coin, you give the king his due" signifies a reciprocal obligation of service or loyalty in exchange for compensation. Powell likely shares this to underline the significance of fulfilling one's duty to a benefactor, which is a recurrent theme across the provided excerpts.
Step-by-step explanation:
The expression "if you take the king's coin, you give the king his due" means that if one accepts payment or favor from someone with power, such as a king, they are expected to provide something of equal value in return, be it service, loyalty, or another form of obligation. It suggests a reciprocal relationship where the acceptance of something valuable comes with conditions or expectations. In the context of Powell sharing this message, it is likely that Powell is emphasizing the importance of loyalty and service to those who have been compensated or who have benefitted from a ruler or leader's generosity.
This concept of mutual obligation is a common thread in many of the excerpts provided, including those describing vassals who sacrificed for their king, leaders who must satisfy their followers, and servants being reminded of their duties toward a throne.