Here, "heart trembles" refers to his emotional pain and suffering. This suffering is because of fear. AT: "I am suffering because I am so afraid" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Becoming very afraid, or terrified, is spoken of as if terror is a thing that falls on a person. AT: "I am very much afraid that I will die" or "I am terrified that I will die" (See: [[rc://en/ta/man/translate/figs-metaphor]])
# Fearfulness and trembling have come on me
Becoming fearful and trembling is spoken of as if fearfulness and trembling are things that come on a person. AT: "I have become very fearful and I tremble" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Feeling horror is spoken of as if horror were a thing that can cover people. AT: "I feel terrible horror" or "I am extremely afraid" (See: [[rc://en/ta/man/translate/figs-metaphor]])