The Noble Truth of Suffering encompasses the non-sentient world of land, rivers, mountains and so forth, as well as the sentient world of all living beings in the six realms. In other words, all sentient beings and what their six consciousnesses (eye, ear, nose, tongue, body and mind) come in contact with are all included in the domain of the Noble Truth of Suffering. Because we are in constant contact with both the sentient and the non-sentient world, suffering manifests around us all the time. We ourselves are also part of it. Even so, people have hardly known correctly the nature of suffering, which in turn leads to much distress. It is therefore so important to understand it well.

- Quote from The Right View, "The Four Noble Truths—the Path Out of Samsara"