مسند امام احمد بن حنبل · Hadith 559

It was narrated that Abu Salih, the freed slave of 'Uthman bin 'Affan (RA) said: i heard 'Uthman (RA) say on the m inbar : O people, I concealed from you a hadeeth that i heard from the Messenger of Allah (PBUH) for fear that you would scatter away from me, then I thought that i should tell it to you, and let each one choose for himself what he thinks is best. i heard the Messenger of Allah (PBUH) say: "Guarding the border for one day for the sake of Allah is better than a thousand other days doing other deeds.”