Sa'id bin Aws al-Ansari narrates from his father that the Prophet (peace and blessings be upon him) said: "When it is the day of Eid al-Fitr, the angels stand along the roads and call out loudly: 'O assembly of Muslims! Go forth to your Generous Lord, who bestows good and will grant a reward for it. You were commanded to stand in prayer at night, and you did so; you were commanded to fast in the day, and you fasted and obeyed your Lord, so now receive your reward!' When the people have prayed, a caller calls out: 'Indeed, your Lord has forgiven you, so return to your homes rightly guided.' So it is the day of reward, and in the heavens this day is called 'the Day of Reward.'" In one narration the words are "Merciful Lord" instead of "Generous Lord," and He says: "I have forgiven you all your sins."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains Jabir al-Ju'fi, whom Sufyan al-Thawri declared thiqah (trustworthy); he narrated from him, and Shu'bah also narrated from him, but people declared him da'if (weak), and he is matruk (abandoned).