I say, and with Allah's success: If he made an effort and thought he was a recipient, then it became clear that he is not a recipient, such as discovering the wealth of the one he gave it to, or their disbelief, or that he is his father, or his son, or a Hashemite, it suffices for him regarding the zakat, and he is not required to pay the zakat again. However, if he paid the zakat without making an effort or after doubt, or if he made an effort and thought he was not a recipient, it does not suffice for him, and he must pay the zakat again; as narrated by Ma'n ibn Yazid, may Allah be pleased with him, who said: 'Abu Yazid had taken out dinars to give 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 brought the case 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.' This is in Sahih al-Bukhari 2: 517, as in Al-Durr Al-Muntaka 1: 225, and Allah knows best.