22-8 Muhammad ibn al-Hassan ibn Ahmad ibn al-Walid - may God be pleased with him - narrated that Muhammad ibn al-Hassan al-Saffar quoted Yaqoob ibn Yazid, on the authority of Uthman ibn Isa who linked it up through a chain of narrations to Aba Abdullah as-Sadiq (MGB),

“If one takes a female slave and doesn’t have sex with her once every forty days, he would be held responsible for her sins.”