It is narrated from Ja'far bin Muhammad, from his father, that Sayyiduna Ali (may Allah be pleased with him) said that.
Imam al-Shafi'i (may Allah have mercy on him) said: It is narrated from Sayyiduna Umar (may Allah be pleased with him) that he held some craftsmen liable, through a chain weaker than this, and we do not know either of the two to be established.
He said: It has also been narrated from Sayyiduna Ali (may Allah be pleased with him), through another chain, that he did not hold any hired worker liable, through a chain whose like is not established.
It is established from Ata bin Abi Rabah (may Allah have mercy on him) that he said: There is no liability on a craftsman, nor on a hired worker.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإجارة / 11665