Mount Carmel is not the tallest mountain in the area, but it often symbolizes the land's beauty and richness.
the serpent: In the ancient Near East, people saw the sea as a symbol of chaos, often opposing the national god (compare Psalms 74:14; 89:10; 104:26). The biblical text does not treat the sea monster as a god. Leviathan, also called Rahab, is shown as a creature under the Lord’s authority (Psalm 89:9–10). God commands and judges this creature, showing his power over it (Isaiah 27:1).
In this passage, Amos shows that God has power over everything. Even the sea serpent must obey him and serve his purposes.