It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that Sayyiduna Bilal (may Allah be pleased with him) came to the Prophet (peace and blessings be upon him) to inform him of the morning prayer, and he (peace and blessings be upon him) said: "Tell Sayyiduna Abu Bakr (may Allah be pleased with him) to lead the people in prayer." Then he came back to him (peace and blessings be upon him) again and sensed a heaviness in him (peace and blessings be upon him) (due to illness), and he (peace and blessings be upon him) said (again): "Tell Sayyiduna Abu Bakr (may Allah be pleased with him) to lead the people in prayer." So he went and called the adhan, and he added to his adhan: 'Al-salatu khayrun min al-nawm' (Prayer is better than sleep). The Prophet (peace and blessings be upon him) asked him: "What is this that you have added to your adhan?" He said: I saw heaviness in you, so I wanted you to become energetic. He (peace and blessings be upon him) said: "Go and keep it (included) in your adhan, and tell Sayyiduna Abu Bakr (may Allah be pleased with him) to lead the people in prayer."
No one narrated this hadith from Ibn Qusayt (may Allah have mercy on him) except Ma'mar (may Allah have mercy on him), and no one from Ma'mar (may Allah have mercy on him) except Abdullah bin Nafi' (may Allah have mercy on him).
Hadith Referenceالمعجم الأوسط / باب الميم / 7524
Hadith Gradingمحدثین:تفرد به مروان
Hadith Takhrij«قال الطبراني: لم يروه عن الزهري إلا النعمان تفرد به مروان «الإعلام بسنته عليه الصلاة والسلام بشرح سنن ابن ماجه الإمام، ج 4، ص 84»» «أخرجه الطبراني فى «الأوسط» برقم: 4158»