‘A’isha said that the prayer was prescribed as consisting of two rak'as, and after God's Messenger emigrated it was prescribed as four, but prayer while travelling was left according to the original prescription. Zuhri said he asked ‘Urwa why ‘A’isha said prayers in the complete form and he replied that she interpreted the matter herself as ‘Uthman did. (Bukhari and Muslim.)
Hadith Referenceمشكوة المصابيح / كتاب الصلاة / 1348
Hadith Gradingالألبانی:مُتَّفَقٌ عَلَيْهِ | زبیر علی زئی:متفق عليه
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «متفق عليه، رواه البخاري (350) و مسلم (685/1)»