Does the Holy Qur'an specifically declare 'alcohol' or wine prohibited (haram)? Some people argue that it does not. Therefore, these people contend that a Muslim can consume alcohol as long as it does not cause a loss of sanity and he does not fall into the state of mindlessness. Please provide Qur'anic reference in support of your reply.
It would be safe to say that there was no need for the Holy Qur'an to expressly declare alcohol haram. All intoxicants are already known to be harmful through our innate guidance. The Islamic Shari'ah takes these dictates of nature for granted. While pointing towards this abhorrence for liquor the Qur'an asks its followers to abstain from consuming it:
Hence, it does not mean that we can take as much quantity of wine that does not cause inebriation. Many things are forbidden because they can eventually lead one to the undesired state, which we are required to refrain from. Take for example the matter of fornication. The Holy Qur'an while giving the directive of the prohibition of fornication enjoined upon the Muslims not to draw near fornication. That means that no one should indulge in activities that are likely to lead him or her into committing fornication. Similarly, one cannot draw a line between the quantity which casts intoxication and which does not. Therefore, one cannot be allowed to take even a small amount of it. An Islamic state can forbid it on the ground of restriction on the means, which are likely to lead one to the state of inebriation.
O you who believe: this liquor and gambling and idols and these divining arrows are abominations devised by Satan. Avoid them that you may succeed. Satan seeks to stir up enmity and hatred among you by means of liquor and gambling and to keep you from the remembrance of Allah and from the prayer. Will you not then abstain from them? (5:90-1)