مسائل المنتخبه (Articles Of Islamic Acts) - الخوئي، السيد أبوالقاسم - الصفحة ٣٠ - HOW A PURE THING BECOMES IMPURE

not necessary that he should inform others about it. However, if his contacts with the other guests are such that there may be a possibilityof his becoming impure owing to their becoming impure he should inform others about the impurity of the food when the meals are over.
١٤٧. If a thing which has been borrowed becomes impure and its owner uses it for purposes for which its being pure is essential (e.g. utensils which are used foreating and drinking) it is obligatory for the borrower to inform the owner about its having become impure. However, if the thing falls under the category of dress it is notnecessary for him to inform the owner about its having become impure although he may be knowing that the owner uses it while offering prayers because purity of dress is notthe real condition for prayers.
١٤٨. If a child says that a thing is impure or that he has washed and purified it with water his word should not be accepted. In case, however, a child who is goingto attain the age of puberty says that he has washed and purified a thing with water when the thing is in his possession or he is reliable, his word should be accepted andthe same orders apply if he says that a thing is impure.