What is the ruling on selling iron to a company that may build with it something containing what is wrong?
Machine translationRead the Arabic original
The questioner : The question is regarding the dealings of Muslims, for example, a Muslim who is a major supplier dealing with a large company, for instance. For example, I used to sell iron next to them, and the beer company asked me to buy iron. So, is it permissible for me, for example, to provide this iron?
The Shaykh : The answer is: If you know that with this iron they intend to build a tavern or a shop where they will sell intoxicants, then it is not permissible. However, if you know that they intend to build a house in which there is no apparent evil, like the first case, then it is permissible. But if both of these are hidden from you, then leave what causes doubt for what does not cause doubt.
The Shaykh : The answer is: If you know that with this iron they intend to build a tavern or a shop where they will sell intoxicants, then it is not permissible. However, if you know that they intend to build a house in which there is no apparent evil, like the first case, then it is permissible. But if both of these are hidden from you, then leave what causes doubt for what does not cause doubt.
Source
سلسلة الهدى والنور، المجلس 64 — d3watuna.com (47:14)
The Arabic text is a machine transcription of the audio recording.