Musannaf Ibn Abi Shayba 13:1614

Abu Bakr narrated to us, he said: Jarir narrated to us, from Mughira, from al-Harith al-'Ukli and his companions, and from 'Ubaydah, from Ibrahim, they said: "A loan is due immediately, even if it was for a fixed term." And Abu Bakr adopts this [position].