Musannaf Ibn Abi Shayba 18:1170

Abu Bakr narrated to us, he said: Ibn Fudayl narrated to us, from Layth, from Mujahid and 'Ata, they both said: A man is not to be retaliated against (in Qisas) for his parents, even if they kill him patiently (i.e., by holding him down or restraining him).