Umm al-Mu'mineen Sayyida Aisha (may Allah be pleased with her) narrated: In the beginning, the obligatory prayer in residence and on a journey was two rak'ahs. Then, the prayer during travel remained two rak'ahs, while the prayer in residence was completed to four rak'ahs. Salih bin Kaysan said: I narrated this hadith to Umar bin Abdul Aziz (may Allah have mercy on him), so he asked: Did Urwah (may Allah have mercy on him) narrate to me that Sayyida Aisha (may Allah be pleased with her) used to perform four rak'ahs (complete prayer) during travel? Salih says: One day I saw Urwah (may Allah have mercy on him) with Umar bin Abdul Aziz (may Allah have mercy on him), so I asked him: How did you narrate that hadith on the authority of Aisha (may Allah be pleased with her)? So he narrated the hadith to me in the same way as he had narrated before. (Upon hearing this) Umar bin Abdul Aziz (may Allah have mercy on him) said to Urwah: You narrated to me that Sayyida Aisha (may Allah be pleased with her) used to perform four rak'ahs (complete obligatory prayer) during travel. Urwah (may Allah have mercy on him) said: Yes! That is how it is.