Answer:
The purpose is to highlight the importance of what he is going to say.
Explanation:
When the author uses repetition to say "… let us be very clear, and make very clear to all the world what our motives and our objects are," he is drawing the attention of listeners and readers and highlighting the importance of what he is going to speak. This makes the public pay close attention to his words, as these words will have a strong impact and must be very well understood and kept, as they present something essential and important.
