* As faithful as a dog: This is a classic and well-understood simile, emphasizing loyalty and devotion.
* As faithful as a compass: This highlights unwavering direction and reliability.
* As faithful as a promise: This emphasizes keeping one's word and being dependable.
* As faithful as the stars: This evokes a sense of unchanging and steadfastness, like the stars in the night sky.
* As faithful as a beacon: This emphasizes guiding and leading someone reliably.
* As faithful as a guardian angel: This implies unwavering protection and support.
Ultimately, the best simile is the one that best captures the specific kind of faithfulness you are trying to convey.