Does one have to purify the house and its rooms for prayer after a young man from among the people of innovation brought a dog into the house and refused to remove it, based on the Maliki and Shia view that impurity applies only when a dog licks a vessel? And does one have to change clothes when touching or being licked by a dog?

Everything licked by a dog or touched by its urine or feces must be purified, due to the impurity of the dog. It is not permissible to imitate the opinion that the dog is pure. What is obligatory is to follow the preponderant opinion among scholars' sayings, and if no preponderant opinion is apparent in the matter, then it is better to follow what is more cautious. Scholars have permitted owning a dog for legitimate purposes such as guarding, provided it is kept away from the living area, because it is inherently impure and prevents the entry of angels. As for caring for dogs and bringing them into homes, this is an alien custom that contradicts the Sharia and from which harm is feared.