The definitive verse forbidding alcohol (and other intoxicants) is found in Surah Al-Ma'idah (5:90-91). The verse states: "O you who have believed, indeed, intoxicants (khamr), gambling, [sacrificing on] stone altars, and divining arrows are but defilement from the work of Shaytan, so avoid it that you may be successful."
The prohibition of alcohol in the Qur'an was revealed gradually, in stages:
In Surah Al-Baqarah (2:219), the Qur'an acknowledged that there is both sin and benefit in wine and gambling, but stated that the sin is greater than the benefit. This was an initial discouragement, not a full prohibition.
In Surah Al-Nisa (4:43), Muslims were told not to approach prayer while intoxicated, restricting the times when drinking was permissible.
Finally, in Surah Al-Ma'idah (5:90-91), the complete and unequivocal prohibition was revealed, commanding believers to avoid intoxicants entirely and categorising them as an abomination from the work of Shaytan.
The verse in Surah Al-Ma'idah is considered the final and definitive ruling (hukm) on the matter because it was the last to be revealed on this subject and uses the strongest language of prohibition. Al-Imran does not contain a specific verse on the prohibition of alcohol.