History bears witness that the process of various people’s religiosity in all the divine religions had been in a way such that after the death or martyrdom of every prophet or every messenger among people the predominant religion would fade out gradually until they put aside the religion and the recommendations of the prophet and turned back to the methods of their astray forefathers. But then another prophet would come and revive the religion once again. In this way, the method of the new prophets and messengers was that they started with propagating very simple and basic issues, so they would gradually and patiently acquaint people with various religious issues.
One of the problems facing humanity over the history is the issue of drinking wine which has deviated man and brought him miseries. For this reason, one of the goals of the prophets was to forbid people from drinking wine. The sixth Imam, Imam Ja’far Sadiq, peace be upon him, says that whenever God sent a prophet to his people, He would, in order to complete the religion, make prohibition of drinking wine among one of the main injunctions of that religion.
This process was also followed in the religion of Islam as in any other divine religions. Before wine was declared forbidden some Muslims used to drink wine in the very early period of Islam. They were addicted to it until the Holy Prophet of Islam (S) gradually announced to people the rule regarding drinking wine. However, since some people were used to committing evil acts due, largely, to their ignorance, so the Holy Prophet (S) announced such laws gradually, and led people to the ultimate goal step by step and sympathetically.
In any case, if anything had been harām in the previous religions and now it is halal in Islam or vice-versa, we must stick to the commands of Islam which is the most perfect and most complete of all the religions.
 - Vide: Askari, Sayyid Murtaza, Islamic Beliefs in the Holy Quran, translated by Karami, Muhammad Jawad, vol.2, p. 336 – 337, Islamic Scientific Assembly, first edition, 1378 (1999).
 - Kulayni, Muhammad bin Ya’qub, Al-Kafi, vol.6, p. 395, Dar al-Kutub al-Islamiyah, Tehran, fourth edition, 1407 A.H.
 - Tabatabai, Sayyid Muhammad Hussein, Al-Mizan fi Tafsir al-Quran, vol.2, p. 193 and 194, Islamic Publications Office, Qom, fifth edition, 1417 A.H.
 - Vide: Ibid, vol.2, p. 193, and 194; and vol.6, p. 117 and 118. Allamah Tabatabai says in his Tafsir al-Mizan, “Human beings, because of their animal tendencies, eagerly run towards the satisfaction of their lust. Lustful activities easily contaminate the environment, in contrast to chastity and piety. It is easy to acquire a bad habit and very difficult to leave it. That is why Allah legislated such laws gradually, and led people to the ultimate goal step by step and sympathetically. One of those widely-spread evils was the drinking of alcohol.”
 - Vide: indexes “Islam and Rationality”, question 50; “Reasons for the Truthfulness of Islam”, question 275.