The two cases are when he says, “Spend on it,” or says nothing and the depositary does not spend on it. In these two cases, if the animal dies, he is liable, because he has been negligent—just as he would be liable if he placed it in bitter cold that it could not withstand, or in intense heat that it could not withstand.
It is understood from the author’s words that if its owner says, “Do not spend on it,” and it then dies, the depositary is not liable. This is based on the view that liability for an animal which dies from hunger or thirst is like liability for inanimate property, which has no life. If a person destroys inanimate property with its owner’s permission, he is not liable. It is like the case where the owner permits him to slaughter it and he slaughters it: he incurs no liability.
This is what the author—may Allah have mercy on him—said, but it is open to question. The second view is that he is liable, because this is a life that must be protected; it is not like property. Property does not suffer, whereas this living creature suffers. Leaving it to die of thirst and hunger is a sin for which a person will be punished in the Fire. It is authentically reported from the Prophet ﷺ that “he saw in the Fire a woman who was punished because of a cat she had confined: she neither fed it nor let it go” (1).
Its owner has permitted him to do something unlawful, but it is not permissible to comply with anything unlawful. Therefore, he is liable, for he could have said to the owner—when he told him not to spend on it—“In that case, I will not accept it,” because I would thereby incur sin.