Full Sharh — Mishkat al-Masabih 1276
وَعَنْ عَائِشَةَ قَالَتْ: فُرِضَتِ الصَّلَاةُ رَكْعَتَيْنِ ثُمَّ هَاجَرَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَفُرِضَتْ أَرْبَعًا وَتُرِكَتْ صَلَاةُ السَّفَرِ عَلَى الْفَرِيضَةِ الْأُولَى. قَالَ الزُّهْرِيُّ: قُلْتُ لِعُرْوَةَ: مَا بَال عَائِشَة تتمّ؟ قَالَ: تأولت كَمَا تَأَول عُثْمَان
English Translation
‘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.)
Source
Mishkat al-Masabih(مشكاة المصابيح)
Prayer
Hadith Number
1276