Looking at the narrations below, what is the Sunnah?
To stand and drink, or to sit whilst drinking?
a) Rasulullah (sallallahu ‘alayhi wasallam) said “No person should stand and drink water, and if one forgetfully stood and drank it, it should be vomited out” (Sahih Muslim, Hadith: 2026)
b) Imam Ahmad narrated that Sayyiduna ‘Ali ibn Abi Talib (radiyallahu ‘anhu) drank whilst standing, and the people looked at him as if they objected to that. He said: ‘What are you looking at? If I drink whilst standing, I saw Nabi (sallallahu ‘alayhi wasallam) drink whilst standing, and if I drink sitting, I saw Nabi (sallallahu ‘alayhi wasallam) drink whilst sitting.’
Imam Bukhari (Hadith: 5615) narrated from Sayyiduna ‘Ali (radiyallahu ‘anhu) that he drank whilst standing then he said: ‘Some people say it is makruh [disliked] for one of you to drink whilst standing, but I saw Nabi (sallallahu ‘alayhi wasallam) doing what you have seen me do.’
You have cited two types of Hadiths;
a) A Hadith that discourages standing and drinking.
b) Hadiths that show permissibility of drinking whilst standing.
There are several narrations that support each of the above. Refer to ‘Umdatul Qari, Hadith: 5615.
There is no contradiction in the above, if understood correctly.
Numerous Hadith Scholars, Like ‘Allamah Khattabi, Ibn Battal, Imam Baghawi, Imam Nawawi, Hafiz Ibn Hajar Al-‘Asqalani and others (rahimahumullah) have explained that the Hadith which discourages standing is explaining the ideal, and it is therefore Mustahabb (recommended) to drink [and eat] whilst seated.
The opposing Hadith is actually showing the permissibility of standing, and not the recommended practice.
Some ‘Ulama have mentioned that standing and drinking is actually harmful to health, and could even affect the kidney.
As a rule, there is no contradiction between a deed being permissible but not ideal.
Our Nabi (sallallahu’alayhi wasallam) -in addition to habitually practicing on the ideal- would sometimes also practice on what was not ideal, merely to demonstrate its permissibility for the Ummah. There are several examples of this. The topic in question is one of them.
In short, the proper Sunnah is to sit and drink, but if one stands it will still be permissible.
Refer: Fathul Bari and ‘Umdatul Qari, Hadith: 5615-5617.
And Allah Ta’ala Knows best.