Sayyiduna Anas (may Allah be pleased with him) narrates this as a marfu' hadith (The Prophet (peace and blessings be upon him) said:) "An angel has been appointed over the Scale. The son of Adam will be brought and made to stand between the two pans of the Scale. If his scale is heavy, the angel will call out in a voice that all creation will hear: 'So-and-so has become fortunate with a fortune after which he will never be wretched.' And if his scale is light, the angel will call out in so loud a voice that all creation will hear it: 'So-and-so has become wretched with a wretchedness after which he will never be fortunate.'"
Imam al-Bazzar recorded it; its chain contains Salih al-Murri, whose weakness is agreed upon.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب البعث / 18394