Ahmad added to the end of the above Hadith, the story of BIlal's statement in the Fajr Adhan (morning prayer call):

as-Salatu khairun minan-nawm - "Prayer is better than sleep".

وَزَادَ أَحْمَدُ فِي آخِرِهِ قِصَّةَ قَوْلِ بِلَالٍ فِي آذَانِ اَلْفَجْرِ: { اَلصَّلَاةُ خَيْرٌ مِنَ اَلنَّوْمِ } [1]‏ .‏