Musannaf Ibn Abi Shayba 28:494

Isma'il ibn 'Ayyash narrated to us, from 'Abd al-Rahman ibn Ziyad ibn An'am, from Khalid ibn Abi 'Imran, who said: I said to al-Qasim ibn Muhammad and Salim ibn 'Abd Allah: "We have a servant who makes pottery in the land of the enemy, then he sells it, and the earnings are gathered, and he spends [the money] on us." They said: "There is no harm in that."