Sunan Ibn Majah Book 16, Hadith 38
“Three things cannot be denied to anyone: water, pasture and fire.”
“The Muslims are partners in three things: water, pasture and fire, and their price is unlawful.”
“O Messenger of Allah (ﷺ), what are the things which are not permissible to withhold?” He said: “Water, salt and fire.” She said: “I said: 'O Messenger of Allah (ﷺ), we know what water is, but what about salt and fire?” He said: “O Humaira', whoever gives fire (to another), it is as if he has given in charity all the food that is cooked on that fire. And whoever gives salt, it is as if he has given in charity all that the salt makes good. And whoever gives a Muslim water to drink when water is available, it is as if he freed a slave; and whoever gives a Muslim water to drink when there is no water available, it is as if he brought him back to life.”