It is narrated from Abu Ja'far that Umar bin Khattab (may Allah be pleased with him) saw Abdullah bin Ja'far wearing two dyed garments while in the state of ihram, so he asked: What are these garments? Ali bin Abu Talib (may Allah be pleased with him) said: I do not consider it necessary for anyone to teach us the Sunnah. At this, Umar (may Allah be pleased with him) remained silent.
Hadith Referenceمسند الإمام الشافعي / كتاب الحج / 846
Hadith Takhrijاسناده ضعيف لإنقطاعة فان ابا جعفر لم يدرك عمر بن الخطاب و علی بن ابی طالب : اخرجه البيهقى 59/5 - وفى المعرفة السنن والآثار له (2858)۔