Shaikh Muqbil ibn Haadi al-Waad’iee rahimahullah was asked:
Question: If a Muslim sells in his store some haram things, is all of his money haram?
Answer: No, in accordance to what he sells. The wealth remains with suspicion and ambiguity. Piety/cautiousness (الورع ) is to leave it off.
As for him, then the sin [on him] is in extent to what he sells of haram. The Messenger (ﷺ) said as in the Musnad of Imam Ahmad from the Hadith of Jabir and Ka’ab ibn ‘Ujrah and the meaning is similar:
إيما جسد نبت من حرام فالنار أولى به
“Any body that is nourished from Haram, then the fire is more deserving of it”
[Saheeh Musnad no. 260]
However, for other than him, piety/cautiousness is to leave it off. Otherwise, the Prophet (ﷺ) used to deal with the jews and the jews used to call him to food and he knew that they used to deal with usury.
[Taken from Ghaartul-Ashritah 2/223]
Faisal ibn Abdul Qaadir ibn Hassan