What is the ruling on selling prohibited goods like pork or wine?
Whatever is forbidden in and of itself, such as liquor, pork, images, impure things, and musical instruments, then its sale to others is also prohibited to both Muslim and non-Muslim customers.
Goods that will surely be used for unlawful purposes may not be sold, even if the product is lawful in and of itself. This, however, is only in cases where it is highly likely that the merchandise will only be used for an unlawful purpose and is not something to be based on conjecture and suspicion. On this basis, scholars have declared it unlawful to sell weapons at time of civil war and grapes to a winery.
This principle is derived from Allah’s saying: “Help you one another in virtue, righteousness and piety; but do not help one another in sin and transgression”.
It is also indicated by what was related by Anas bin Mâlik that the Prophet (peace be upon him) cursed ten people on account of liquor: he cursed the one who presses it, the one who commissions others to press it, the one who drinks it, the one who serves it to others to drink, the one who delivers it, the one to whom it is delivered, the one who sells it, the one who buys it, and the one who receives its price.” [Musnad Ahmad (4772), Sunan al-Tirmidhî (1295), Sunan Abî Dâwûd (3674) and Sunan Ibn Mâjah. It is an authentic hadîth.]
Source: Islam Today
-- Al Arabiya Digital