Authubillaahi min ash-Shaytaani rajeem
Bismillaahi ar-Rahmaan ar-Raheem, Allaahumma salay ‘ala Muhammad wa ‘ala aalay Muhammad kamaa salayta ‘ala aali Ibraaheem innaka Hameedum Majeed. Allaahumma baraak ‘ala Muhammad wa ‘ala aalay Muhammad kamaa baraakta ‘ala aali Ibraaheem innaka Hameedum Majeed.
Abu Hurayra reported Rasulullaah said:
لاَ يَشْرَبَنَّ أَحَدٌ مِنْكُمْ قَائِمًا فَمَنْ نَسِيَ فَلْيَسْتَقِئْ
None of you should drink standing; and if any one forgets, he must vomit.
[Saheeh Muslim, Book of Drinks]
The hadeeth is Saheeh and there is nothing ambiguous about it. The Prophet had clearly prohibited drinking while standing. And this prohibition is general to all types of drinks.
There are other authentic narrations from the Sahaabah, mentioning that they had seen Rasulullaah drink while standing, but they had never reported any verbal sayings of the Prophet permitting drinking and standing at the same time. This is understood from several angles:
Firstly, the prohibition was after, therefore what he did before was abrogated.
Secondly, Rasulullaah’s words are wahy from Allaah aza wa jal, hence, they have divine assurance while his actions did not. The possibility of the Prophet making a mistake does exist as there are several Saheeh ahadeeth proving such incidences occurring. One being while cutting the prayer short by mistake [Saheeh al-Bukhaari, Book of Prayer & Saheeh Muslim Book of Prayer].
Thirdly, whatever a Sahaabi says or does is not wahy from Allaah aza wa jal and cannot be considered as evidence. Even if he/she reported witnessing the Prophet doing something, unless he/she was quoting the Prophet himself.
Fourthly, if anyone claims that drinking whilst standing is merely disliked, or that it is recommended to not stand while drinking. It is obligatory upon them to bring clear evidence from the book of Allaah aza wa jal or authentic sayings of Rasulullaah himself mentioning such conclusions. Did the Prophet say it was disliked or recommended? If his prohibition was a recommendation, where are the other sayings of Rasulullaah telling us that he did not forbid us but only recommended it to us? Without this, such a conclusion is a bid’ah.
Nothing can be considered an obligation, recommendation, disliked or prohibited except through wahy from Allaah aza wa jal. This was the duty of Rasulullaah to tell us and teach us the deen in its totality:
يَا أَيُّهَا الرَّسُولُ بَلِّغْ مَا أُنزِلَ إِلَيْكَ مِن رَّبِّكَ ۖ وَإِن لَّمْ تَفْعَلْ فَمَا بَلَّغْتَ رِسَالَتَهُ ۚ وَاللَّهُ يَعْصِمُكَ مِنَ النَّاسِ ۗ إِنَّ اللَّهَ لَا يَهْدِي الْقَوْمَ الْكَافِرِينَ
O Messenger! Proclaim which has been sent down to you from your Lord. And if you do not, then you have not conveyed His Message. Allaah will protect you from mankind. Indeed, Allaah guides not the people who disbelieve.
[Surah al-Ma’idah 5:67]
Therefore, anyone who claims anything without the Prophet actually saying it, has innovated into Islaam that did not exist before. Our obligation is to follow the wahy, as Allaah aza wa jal said:
اتَّبِعُوا مَا أُنزِلَ إِلَيْكُم مِّن رَّبِّكُمْ وَلَا تَتَّبِعُوا مِن دُونِهِ أَوْلِيَاءَ ۗ قَلِيلًا مَّا تَذَكَّرُونَ
Follow what has been revealed to you from your Lord and do not follow other than Him any allies. Little do you remember.
[Surah al-‘A’raaf 7:3]