When the slave uttered those words to Abu Bakr, Abu Bakr thrust his hand into his mouth and vomited everything he had eaten—he brought it all up from his stomach. Why did he do that? So that his body would not be nourished by anything unlawful. The money in question was illicit, for it was payment for an illicit act, and the Prophet (peace and blessings be upon him) said, “When Allah forbids a thing, He also forbids its price.”

Therefore, any wage earned for performing something forbidden is itself forbidden. One instance of this is people who lease their shops to barbers who shave beards; the rent they receive is unlawful and not permissible for the shop owner, because the premises were hired for a prohibited activity.

Another example is renting out property to banks. Such leasing is unlawful, for virtually all of a bank’s dealings are prohibited. Even if a permissible transaction occasionally occurs, it is incidental to the very reason the bank was established—namely, usury. If a person leases his house or store to a bank and the bank conducts usurious business there, the rent is unlawful and may not be taken by the owner of the house or the store.

Likewise, anyone who rents premises to a seller of obscene magazines or publications that corrupt minds with vile ideas and conflict with the Sacred Law is acting impermissibly. Allah, the Exalted, has said, “And do not help one another in sin and aggression” (Qur’an 5:2), and renting property to such people is helping them. The Prophet (peace and blessings be upon him) also said, “When Allah forbids a thing, He forbids its price.”