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.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السرقة / Q17230