Abu Dawud Book 002, Hadith Number 0426.

Chapter : Not known.

Narated By Umm Farwah : The Apostle of Allah (pbuh) was asked: Which of the actions is best? He replied: Observing prayer early in its period.

Al-Khuza'i narrated in his version from his aunt named Umm Farwah who took the oath of allegiance to the Prophet (pbuh): He was questioned.