Imam al-Shafi'i (may Allah have mercy on him) said: "His hand is to be cut."
And (Imam Sufyan) al-Thawri (may Allah have mercy on him) narrated it from Isma'il bin Muslim, from Imam al-Hasan al-Basri (may Allah have mercy on him), except that he said: "Whether he is free or a slave." And al-Thawri differed from him regarding the free man.
Ibn Abi al-Zinad narrates from his father, from the jurists of the people of Madinah, that whoever steals a small slave, or a non-Arab who has no means (of protecting himself), his hand is to be cut. And it is narrated from Umar bin al-Khattab (may Allah be pleased with him) that he did not hold that the hand be cut for them; he said: These are khallabun (deceivers).
Our scholars said: Its meaning concerns the slave when he is of sound mind, for it is narrated from Umar (may Allah be pleased with him) that he cut the hand of a man for a boy who was stolen.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السرقة / 17230