Lady Aisha (may Allah be pleased with her) narrates that (in the beginning of Islam) the prayers for travel and residence were made obligatory as two rak‘ahs each. Then, when the Messenger of Allah (peace be upon him) settled in Madinah Munawwarah, two rak‘ahs were added to the prayer in residence, and the Fajr prayer was left as it was due to its lengthy recitation, and the Maghrib prayer was also left as it was because it is the witr (odd-numbered prayer) of the day. “Imam Abu Bakr (may Allah have mercy on him) says that this hadith is gharib (rare). To my knowledge, no narrator except Mahbub bin Hasan has narrated it in a musnad form. The students of Dawud, while narrating this report, have said « عن الشعبي عن عائشه » (that is, they did not mention Masruq, the teacher of Shu‘bi), whereas Mahbub bin Hasan has mentioned Masruq by name and narrated the chain as connected.