The two preceding reports serve only to show what is preferable and more complete, and Allah knows best.

Explanation
The author, may Allah have mercy on him, said: “Chapter: The undesirability of drinking from the mouth of a water-skin or the like, and clarification that this is a recommendation of avoidance, not an absolute prohibition.”

Among the etiquettes of drinking is that one should not drink directly from the mouth of a water-skin or leather container, because the Messenger of Allah ﷺ forbade it. The reason is that water in former times was not especially clean; once stored in a skin or container it could contain harmful things—splinters, insects, and the like—well known to those who used such vessels. For that reason the Prophet ﷺ forbade ikhtināth al-asqiyah, meaning that a person would bend or break open the mouth of the skin in order to drink.

It is related that a man once drank in this way and a snake came out of the water-skin; this is obviously dangerous, as the snake might bite or otherwise harm him. Hence the prohibition concerns drinking from the mouth of a water-skin. It does not apply to drinking from a tap or from the jars in which water is now stored, for these are known and clean and are like ordinary drinking vessels.

However, when there is a need, there is no objection to drinking from the mouth of a water-skin—for example, if a person needs water but has no cup, he may drink straight from the skin. Accordingly, the prohibition, as the author (may Allah have mercy on him) explained, is one of disapproval (karāhah), not of outright unlawfulness.

From the last hadith one also learns that it is permissible for a person to drink while standing when necessity calls for it, even though the Prophet ﷺ and his family