Musannaf Ibn Abi Shayba 26:396

Hushaym narrated to us, from Abu Bishr, from ‘Ata’, that a man emancipated a slave of his as a *sa’ibah* (a type of pre-Islamic emancipation where the master renounces all rights to the slave). The slave died and left behind wealth. Ibn Mas’ud was asked about this, and he said: "The people of Islam do not practice *sa’ibah*. Only the people of the Pre-Islamic Era (Jahiliyyah) used to practice *sa’ibah*. You are his master, the guardian of his favor, and the person most entitled to his inheritance." He added: "And if you feel any hesitation regarding anything, then here is the treasury (Bayt al-Mal), for it has many heirs."