The conversation between human and AI assistant.
[|Human|] Detect whether the sentence is a metaphor or not.
[|AI|] This sentence includes a metaphor. In the sentence, "he" is metaphorically referred to as a "rock" in the midst of a tumultuous situation or "troubled sea," representing unwavering support, strength and reliability in difficult times.
[|Human|] 
Detect whether the sentence is a metaphor or not.