These words mean basically the same thing and are used together to emphasize how weak David was. Alternate translation: "weak" (See: [[rc://en/ta/man/translate/figs-doublet]])
Here the word "fear" can be expressed with the adjective "afraid." Alternate translation: "will surprise him and make him afraid" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
It is implied that he intends to kill the king. This can be stated clearly. Alternate translation: "I will kill only the king" (See: [[rc://en/ta/man/translate/figs-explicit]])