Ways of proving Najasat
122. There are three ways of proving the najasat of anything:
One should be certain, or satisfied that something is najis. If one suspects that something may be najis, it is not necessary to avoid it. Accordingly, eating or drinking at stalls and guest houses where public goes to eat, and where people without scruples about najasat frequent, is allowed unless one knows that the food supplied is najis.
If a reliable person who possesses, controls or manages a thing, says that it is najis. For example, if the wife, or a servant, or a maid says that a particular utensil or any other object which she handles, is najis, it will be accepted as najis.
If two just persons testify that a certain thing is najis, provided that their testimony deals with the reason for najasat.
123. If a person does not know whether a thing is Pak or najis because of ignorance, for example, if he does not know whether the droppings of a rat is Pak or not, he should enquire from those who know. But, if he knows the rule, and doubts the nature of particular thing, like when he doubts whether a thing is blood or not, or if he does not know whether it is the blood of a mosquito or a human being, the thing is Pak, and it is not necessary to make investigation or enquiry about it.
124. A thing which was originally najis, and one doubts whether it has become Pak, will be considered as najis. Conversely, if a thing was originally Pak, and if one doubts whether it has become najis, it will be considered Pak. And it is not necessary t o ascertain, even if it is possible to do so.
125. If a person knows that out of the two vessels, or two dresses used by him, one has become najis, but cannot identify it, he should refrain from using both of them. But if he does not know whether it is his own dress, or the dress which is no longer possessed by him, or is the property of some other person, which has become najis, then it is not necessary for him to refrain from using his own dress.