One cannot pray in impure clothes because of the general meaning of the texts which indicate that clothes should be pure when praying. They do not differentiate between dry impurity and wet impurity. Impurity cannot be removed from a garment except by washing it with purifying water. It is not sufficient merely to let the impurity dry out.

The mere fact that a dog passed through a place does not render it impure.

The scholars said that leftover water from which a dog has drunk and the saliva of dogs are impure, and that vessels and garments licked by a dog must be washed seven times, one of them being with earth.