The imagery of "the heart" suggests a relationship of leadership and trust between the society the narrator plans to build and the outside world. It shows when says: "It (the new land or fort) will become as the heart of the earth, lost and hidden at first, but beating louder each day".
The narrator is talking about a place that will be (in the future) the main organ of the outside. Everybody is going to hear of this place and will feel attracted to it, and the brothers and their Councils will be impotent if they try to destroy it because of its effectiveness and central power.
Everything is going to depend on this place.
The imagery of the heart that is used here suggests that the nation that would be built would grow daily to become a very strong place.
The heart is used to depict this new nation. As the beating of the heart gives life, so also will the new country be a central part of the world.
The reason for this answer can be seen in the way that the word heart was used in the sentence.
According to the excerpt, the new nation is going to be at first hidden but they would beat each day like the heart till words about them reach all corners of the earth.
This suggests that the country may be weak at first but with time it would grow to become a very powerful place.
Read more on the anthem here:
https://brainly.com/question/2030902
