✅Answer: Please pay attention to the following narrations:

1 عَنْ مُحَمَّدِ بْنِ يَحْيَى عَنْ مُحَمَّدِ بْنِ الْحُسَيْنِ عَنْ عُثْمَانَ بْنِ عِيسَى عَنْ أَبِي الْمَغْرَاءِ عَنْ أَبِي عَبْدِ اللَّهِ قَالَ: إِنَّ اللَّهَ تَبَارَكَ وَ تَعَالَى أَشْرَكَ بَيْنَ الْأَغْنِيَاءِ وَ الْفُقَرَاءِ فِي الْأَمْوَالِ فَلَيْسَ لَهُمْ أَنْ يَصْرِفُوا إِلَى غَيْرِ شُرَكَائِهِمْ.

📚 Al-Kafi, vol. 3, p. 545

Imam Sadiq (peace be upon him) said: 'Indeed, God, the Blessed and Exalted, has made the wealthy and the poor partners in wealth. So, the wealthy do not have the right to divert (the wealth) to others than their partners (they should not spend the wealth on others than their partners, who are the poor).'

2 أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنِ الْحُسَيْنِ بْنِ عُثْمَانَ عَمَّنْ ذَكَرَهُ عَنْ أَبِي عَبْدِ اللَّه فِي رَجُلٍ يُعْطِي زَكَاةَ مَالِهِ رَجُلًا وَ هُوَ يَرَى أَنَّهُ مُعْسِرٌ فَوَجَدَهُ مُوسِراً قَالَ لَا يُجْزِئُ عَنْهُ.

📚 Al-Kafi, vol. 3, p. 545

Imam Sadiq (peace be upon him) said about a person who gives the Zakat of his wealth to a person whom he considers needy (he thinks is needy and poor) and then finds him to be wealthy: 'It is not sufficient for him (meaning he must repeat his Zakat and give it to its rightful recipients).'

3 الْجَعْفَرِيَّاتُ، أَخْبَرَنَا مُحَمَّدٌ حَدَّثَنِي مُوسَى حَدَّثَنَا أَبِي عَنْ أَبِيهِ عَنْ جَدِّهِ جَعْفَرِ بْنِ مُحَمَّدٍ عَنْ أَبِيهِ أَنَّ عَلِيّاً كَانَ يَقُولُ: الزَّكَاةُ مَضْمُونَةٌ حَتَّى تُوضَعَ مَوَاضِعَهَا

📚 Al-Ja'fariyyat, p. 54

Imam Sadiq (peace be upon him) narrated from his father that Ali (peace be upon him) would say: 'Zakat is guaranteed until it is placed in its proper place.' (meaning that as long as it is not placed in its correct place, the person is responsible for it).

✅Based on the narrations regarding the necessity of placing Zakat in its correct place, if someone gives their Zakat, whether it is Zakat on wealth or Zakat al-Fitr, to a person who is not its rightful recipient, it is not sufficient for them, and they must give it to its rightful recipient. In the case of the question, where a person initially thought someone was poor and gave their Zakat to them, and then it becomes clear that they were not poor, according to the second narration, it is not sufficient for him, and he must pay it again.

Ruling on paying Zakat to an undeserving person

اللَّهُمَّ صَلِّ عَلَی مُحَمَّدٍ وَ آلِ مُحَمَّدٍ

وَ عَجِّلْ لِوَلِیِّکَ الْفَرَجَ وَ الْعَافِیَةَ وَ النَّصْرَ