It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "When Jibril (peace be upon him) comes with revelation, the first thing he conveys to me is 'Bismillahir-Rahmanir-Rahim' (In the name of Allah, the Most Gracious, the Most Merciful)."
Imam al-Tabarani (may Allah have mercy on him) said: "Only Dawud bin Ata narrated this hadith from Musa bin Uqbah."
Hadith Referenceالمعجم الأوسط / باب الحاء / 3480
Hadith Takhrij«أخرجه الدارقطني فى «سننه» برقم: 1167»