It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that a man came to the Messenger of Allah (peace and blessings be upon him) with a black slave-woman and said: "O Messenger of Allah! Freeing a believing slave is obligatory upon me; will this one suffice on my behalf?" The Messenger of Allah (peace and blessings be upon him) asked her (the slave-woman): "Do you testify that there is no god worthy of worship except Allah?" She said: "Yes." He (peace and blessings be upon him) asked: "Do you testify that I am the Messenger of Allah?" She said: "Yes." Then he (peace and blessings be upon him) said (to her owner): "Free her, for she suffices (on your behalf)."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Habib except Qays; and Hunayn is the freed slave of Sayyiduna al-Abbas bin Abd al-Muttalib (may Allah be pleased with him) and the grandfather of Ibrahim bin Abdullah bin Hunayn."
It is like this in the printed Dar al-Haramayn edition, and perhaps the correct name is "bin Abi Hakim".
Hadith Referenceالمعجم الأوسط / باب الميم / 7070
Hadith Takhrij«أخرجه البزار فى «مسنده» برقم: 4749، 5019، وابن حجر فى «المطالب العالية» برقم: 2899، والطبراني فى «الكبير» برقم: 12369، والطبراني فى «الأوسط» برقم: 5523»