What is the meaning of the prophetic Hadith: "People are partners in three: water, pasture, and fire"? And is it permissible to sell grass that grows naturally on land (rain-fed, not irrigated) for a fee, for sheep to graze from it?

People are partners in pasture and water if they are in an open, unowned wilderness. However, if grass grows on land owned by someone, he is permitted to dispose of it through sale or gift. Imam Malik held that the Hadith refers to pasture in open lands and deserts, where the land itself is not owned. The meaning of "he does not prevent the benefit of a well" is that people are partners in water, fire, and pasture.