Is it permissible to borrow from someone whose wealth is known to be unlawful?

It is not permissible to borrow from or deal with a person known for their unlawful transactions, as this necessitates avoiding them. However, if their transactions are mixed between the lawful and the unlawful, then there is no harm in dealing with them, but it is better to avoid them, based on the Prophet's (peace be upon him) saying: "Leave that which makes you doubt for that which does not make you doubt," and "Whoever guards against doubtful matters has indeed safeguarded his religion and his honor," and "Sin is what wavers in your soul and you dislike for people to find out about it."