It is said: If he investigates and thinks that he is a recipient, then it becomes clear that he is not a recipient: as if it becomes clear that the one he gave to is wealthy, or an infidel, or that he is his father, or his son, or a Hashemite, it suffices him, and he is not required to pay the zakat again. However, if he pays it without investigation, or after doubt, or investigates and thinks that he is not a recipient, it does not suffice him, and he must pay the zakat again, as mentioned in Al-Durr Al-Muntaka 1: 225; for it was narrated from Ma'n ibn Yazid, may Allah be pleased with him, who said: "Abu Yazid used to give out dinars in charity and placed them with a man in the mosque. I came and took them and brought them back to him, and he said: 'By Allah, I did not intend you.' So I argued with him before the Messenger of Allah, peace be upon him, and he said: 'You have what you intended, O Yazid, and you have what you took, O Ma'n.'" In Sahih Al-Bukhari 2: 517.