7. Ali ibn Muhammad and others have narrated from Sahl ibn Ziyad from Ali ibn Rayyan who has said the following: “Certain ones of our people once wrote to him (the Imam) through Ibrahim ibn ‘Uqbah, asking abu Ja‘far عليه السلام, about performing Salah (prayer) on prayer mats made in al-Madinah. He (the Imam) wrote in answer, ‘You can perform Salah (prayer) on what is made with threads but not on that which is made with leather stripes.’ Our people were not clear about the meaning of ‘thread’ and ‘stripe’, so I presented a line of poem by Taabbata Sharran (name of a person) that said, ‘As if they are threads of Mariy which are twisted and attached.’ Mariy was a weaving man who worked with ropes and twines.