I brought the Prophet ﷺ a cup of milk from Naqi that was uncovered. He said, "Why did you not cover it, even by placing a stick across it?"Abu Humayd explained, "He only commanded that waterskins be tied at night and that doors be shut at night."
أتيت النبي ﷺ بقدح لبن من النقيع ليس مخمرا، فقال: ألا خمرته، ولو تعرض عليه عودا. قال أبو حميد: إنما أمر بالأسقية أن توكأ ليلا، وبالأبواب أن تغلق ليلا.
Reported by Muslim in the Book of Drinks (2010) via Dahhak Abu Asim, who said, Ibn Jurayj informed us, Abu Zubayr informed me that he heard Jabir bin Abdullah say, Abu Humayd Saadi informed me, and then he related it.His saying, "not covered," means not covered, and takhmir means covering. His saying, "Naqi" with the letter noon, it is said this refers to the place that was protected for the grazing of livestock. His saying, "place a stick across it," means that if you do not cover it with something, then place the stick across it to protect it from contamination.As for Abu Humayd's statement that the waterskins were tied at night, this specification is not found in the hadith itself. That is why Nawawi said in his commentary on Sahih Muslim, "The preferred view among most of the scholars of legal theory, and it is the position of Shafii and others, is that a companion's interpretation, when it contradicts the apparent meaning of the wording, is not binding as proof, and other jurists are not obligated to follow his interpretation."The command to cover the vessel is general, so it cannot be restricted merely on the basis of the narrator's own practice.