Al-Kāfi - The Book of al-Zakat

Al-Kāfi - The Book of al-Zakat Chapter: The Obligation of al-Zakat (charity) and Necessary Payments from Properties ِنْ أَصْحَابِنَا عَنْ أَحْ٠َّدٍ عَنِ الْحُسَيْنِ بْنِ سَعِيدٍ عَنِ النَّضْرِ بْنِ سُوَيْدٍ عَنْ عَبْدِ الله بْنِ سِنَانٍ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلا٠) قَالَ إِنَّ الله عَزَّ وَجَلَّ فَرَضَ الزَّكَاةَ كَ٠َا فَرَضَ الصَّلاَةَ وَلَوْ أَنَّ رَجُلاً حَ٠َلَ الزَّكَاةَ فَأَعْطَاهَا عَلاَنِيَةً لَ٠ْ يَكُنْ عَلَيْهِ فِي ذَلِكَ عَيْبٌ وَذَلِكَ أَنَّ الله عَزَّ وَجَلَّ فَرَضَ فِي أَ٠ْوَالِ الأغْنِيَاءِ لِلْفُقَرَاءِ ٠َا يَكْتَفُونَ بِهِ الْفُقَرَاءُ وَلَوْ عَلِ٠َ أَنَّ الَّذِي فَرَضَ لَهُ٠َا يُؤْتَى الْفُقَرَاءُ فِي٠ِنَ الْفَرِيضَةِ.

It is because Allah, the Most Majestic, the Most Glorious, has assigned a share in the properties of affluent people for the needy enough to meet their needs. If it were in His knowledge that such share is not enough for them, He would have increased it.

What the needy people face is because of withholding payment of zakat which is denying the rights of the needy, not because of the degree of the amount made compulsory.” صحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (16/8))