Explanation of the author's statement: "And if a pure substance is mixed with an impure one, it is forbidden to use either, and one should not investigate which is which."

The Shaykh : He said "And if a pure substance is mixed with an impure one, it is forbidden to use either". "Mixed" means that pure water is mixed with impure water. It is forbidden to use either. Why? Because avoiding impurity is obligatory, and this cannot be achieved except by avoiding both. And whatever is necessary for the completion of an obligatory act is itself obligatory. This is a theoretical analogical proof. It is also supported by the fact that the Prophet (peace and blessings be upon him) said regarding a man who hunts and the game falls into water: he said and he said . He ordered them to avoid it because we do not know whether it is from what is lawful or from what is forbidden. These are two impure waters; we do not know which is lawful for us and which is forbidden. So what is obligatory? The obligation is to avoid both. The operative cause is the statement of the scholars: whatever is necessary for the completion of an obligatory act is itself obligatory. Therefore, it is obligatory to avoid both. This is the second ruling in this issue of confusion. He said "and one should not investigate which is which", meaning one does not look to determine which is the pure and which is the impure. One does not investigate; rather, one avoids both. One does not investigate, even if there are indications. This is the well-known position in the school of thought. The second opinion is that one should investigate, which is the opinion of al-Shafi'i. And this is the correct opinion: that one should investigate. Because the Prophet (peace and blessings be upon him) said in the hadith of Ibn Mas'ud regarding the issue of doubt in divorce: he said . This is a report-based proof for the establishment of investigation in cases of confusion. As for the theoretical proof, we say that among the established principles of the scholars of knowledge is that when certainty is impossible, one reverts to the preponderance of probability. Here, certainty as to which is the impure is impossible for us, so we revert to the preponderance of probability. For this reason, the correct opinion, without doubt, is that one should investigate. If it is more likely in his mind that this is the pure one, he uses it and there is nothing wrong with him, and he avoids the other. Now, these are two issues. The third issue is...