I wrote to Abu Ja'far al-Thani (Imam Muhammad ibn Ali Al-Jawad (as)) concerning clothing made from squirrel (sanjab), mink (fanak), and silk (khazz), and I said: 'May I be your ransom, I would like you not to respond with dissimulation (taqiyya) regarding this matter.' The Imam (as) wrote back in his own handwriting, 'Pray in them.'"