What is the ruling on participating in literary competitions that are sponsored or have their prizes provided by usurious banks?

Prizes are permissible only in competitions involving camels, horses, arrows, and whatever aids in jihad, such as competitions in Quran, Hadith, and Fiqh, due to the Prophet's (peace be upon him) saying: "There is no prize except in archery, camel racing, or horse racing."

If the literary competition aids in spreading and strengthening the religion, then it is permissible to offer prizes in it.

As for participating in literary competitions sponsored by usurious banks, there is no harm in that if the competitions are among those in which prizes are permissible. This is because it is permissible to accept a gift from someone whose wealth is mixed (with unlawful earnings), and the sin of unlawfully gained wealth rests only upon the one who earned it, not upon the one who received it through a permissible means.