Hadith 429

al-Bukhari has: 'Then [(Allah's Messenger (SAW)] emigrated and it was prescribed as four, but prayer while travelling was left according to the original prescription (of two Rak'at).'

وَلِلْبُخَارِيِّ: { ثُمَّ هَاجَرَ, فَفُرِضَتْ أَرْبَعًا, وَأُقِرَّتْ صَلَاةُ اَلسَّفَرِ عَلَى اَلْأَوَّلِ } <sup>1</sup>‏ .‏

Hadith 429 - The Book of Prayer - Bulugh al-Maram - Sunnah.com