The magnitude of the heart is measured by what can disturb you. If it is small like a pond, even a small stone can create big turbulence. If it's like a lake, it needs a bigger stone to create a turbulence. If it's vast, wide like an ocean, nothing can disturb that. Even mountains can fall into the ocean but the ocean remains as it is.
Feelings change, thoughts change, ideas change, body is undergoing changes all the time, but the thirst deep within us is for something that is not changing, that is eternal, that is always, that is the same.
The sign of enlightenment is no complaints and no explanations!