Sahih Ibn Khuzaymah

Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that a man came to the Messenger of Allah (peace and blessings be upon him) and said, "O son of Banu Abdul Muttalib « السَّلامُ عَلَيْك »." The Prophet (peace and blessings be upon him) said, " « وَعَلَيْك » and peace be upon you as well." He said, "I am a man from the branch of Bayaz of the tribe of Sa'd bin Bakr. I am the messenger of my people and their envoy to you. I will ask you some questions and will be strict in my questioning. I will make you swear and will be stern in making you swear." The Prophet (peace and blessings be upon him) said, "O brother of Ibn Sa'd, ask whatever you wish." He said, "Who created you? Who created the people before you? And who will create those who come after you?" The Prophet (peace and blessings be upon him) said, "Allah." He said, "Then I ask you by Allah, did He make you His Messenger?" The Prophet (peace and blessings be upon him) said, "Yes." He said, "Indeed, we have read in your letter and your agent has also informed us that he will collect zakat from our animals and distribute it among our poor. So I ask you by Allah, did Allah command you to do this?" The Prophet (peace and blessings be upon him) said, "Yes." Imam Abu Bakr (may Allah have mercy on him) says that the statement of Allah Almighty « إِن تُبْدُوا الصَّدَقَاتِ فَنِعِمَّا هِيَ » [ سورة البقرة : 271 ] "If you disclose your charity, it is good..." is related to this issue.