It is narrated from Sayyiduna Abdullah bin Amr bin al-As (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "A servant does not become a believer until he believes in the decree (qadar), its good and its evil."
No one narrated this hadith from Abu Yunus (may Allah have mercy on him) except Zafir (may Allah have mercy on him), and Ibn Abi Ghassan (may Allah have mercy on him) is alone in narrating it from him.
Hadith Referenceالمعجم الأوسط / باب الميم / 7043
Hadith Takhrij«أخرجه أحمد فى «مسنده» برقم: 6818، 7105، والطبراني فى «الأوسط» برقم: 1955»