Musannaf Ibn Abi Shayba 28:912

Isma'il ibn 'Ayyash narrated to us, from 'Abdullah ibn Dinar al-Bahrani, that 'Umar ibn 'Abd al-'Aziz said: As for whoever from the people of the earth accepts Islam, then he has what he accepted Islam upon, of family or wealth. And as for his land, it is considered among that which Allah has bestowed as spoils upon the Muslims.