My father, may Allah (swt) be pleased with him, mentioned in his letter to me: 'Know, my son, that the best of the supererogatory (nafl) prayers are the two Rak'ahs of Fajr, followed by the single Rak'ah of Witr, then the two Rak'ahs of Dhuha (mid-morning prayer), then the supererogatory prayers after Maghrib, then the completion of the Night Prayer, and finally, the completion of the daytime supererogatory prayers.'