Hadith: A man who had drunk alcohol was brought to the Prophet (may Allah's peace and blessings be upon him) and he gave the man about forty lashes with two palm branches

عن أنس بن مالك رضي الله عنه «أن النبي صلى الله عليه وسلم أُتِيَ برجل قد شرب الخمر، فجلده بِجَرِيدَتَيْنِ نحو أربعين»، قال: وفعله أبو بكر، فلما كان عمر استشار الناس، فقال عبد الرحمن: أَخَفُّ الحدود ثمانين، «فأمر به عمر».
[صحيح] - [متفق عليه واللفظ لمسلم]

Anas ibn Mālik (may Allah be pleased with him) reported: A man who had drunk alcohol was brought to the Prophet (may Allah's peace and blessings be upon him) and he gave the man about forty lashes with two palm branches. Anas added: “Abu Bakr did the same, but when ‘Umar became the caliph, he consulted the people, and ‘Abdur-Rahmān ibn ‘Awf said: ‘The lightest prescribed punishment is eighty (lashes).' So ‘Umar gave his commands accordingly."
Sahih/Authentic. - [Al-Bukhari and Muslim. This is the wording of Muslim]

Explanation

The Hadīth indicated that the Prophet (may Allah's peace and blessings be upon him) gave a man who had drunk alcohol around forty lashes using palm branches. Abu Bakr (may Allah be pleased with him) applied the same punishment. However, when people started drinking more alcohol after the conquest of the Levant and other countries, where Muslims acquired many grapes and vineyards, ‘Umar (may Allah be pleased with him) consulted the Companions in regard to the punishment. When he consulted ‘Abdur-Rahmān ibn ‘Awf (may Allah be pleased with him), he said that the punishment for drinking alcohol should be escalated and the mildest punishment for drinking alcohol should be eighty lashes. Most of the Companions accepted this suggestion, and this opinion was adopted by the majority of Muslim jurists. The punishment for drinking alcohol was originally established by the Shariah and is not subject to Ijtihād (independent reasoning). Yet, the Ijtihād of the Companions (may Allah be pleased with him) was only used to increase the punishment when drinking alcohol intensified and became rampant and people were not deterred by the previous number of lashes.