The companions of al-Shafi'i said: If the majority is used water, it prohibits it; if it is the minority, it does not.

Ibn 'Aqil said: If what falls into it is of such a nature that if it were vinegar, it would change the water, then it prohibits it; otherwise, it does not.

What we have mentioned from the reports and the apparent state of the Prophet (peace and blessings of Allah be upon him) and his Companions prohibits considering it by the analogy of vinegar, because [vinegar] is one of the most penetrating of liquids and the most pervasive, so even a little of it affects the water. The hadith has indicated the pardon of small amounts of it. Therefore, in this matter, one returns to custom ('urf); so if it is large and excessive, it prohibits [its use], otherwise it does not. If one is in doubt, the water remains upon its purity (tahuriyyah), for it is the original state, and it is not removed by doubt.

Section: If one has some water that is not sufficient for one's purification, and one supplements it with a liquid that does not alter it, performing wudu with it is permissible according to one of the two narrations, because it is pure and has not altered the water, so it does not prohibit [it], just as if the water were in an amount sufficient for purification. The second [narration]: It is not permissible, because we are certain of the occurrence of washing some of his limbs with the liquid. The first [narration] is more appropriate, because since the quality of the liquid did not become apparent upon the water, the ruling of the whole became the ruling of water. What we mentioned for the second narration is invalidated by the case where the water is an amount sufficient for purification and one mixes it with a liquid, then performs wudu with it, and the amount of the liquid or less remains, it is permissible, despite (18) the knowledge that what is used is a part of the water and a part of the liquid, and likewise the remainder, because of the impossibility of separating the water from the liquid. And Allah knows best.

Section: It is not disliked to perform wudu with water heated by something pure, unless it is so hot that it prevents the completion of wudu (isbagh) due to its heat. Among those from whom it was reported that they saw no issue with wudu with heated water are 'Umar, his son, Ibn 'Abbas, and Anas, may Allah be pleased with them. This is the view of the people of the Hijaz and all of the people of Iraq, except for Mujahid (19), and there is no basis for his statement, for Zayd ibn Aslam, may Allah be pleased with him, narrated (20): that 'Umar